Abstract:
A three-dimensional tube puzzle is disclosed as a new modification of Rubik&#39;s Cube™. It consists of plurality of straight and curved cylindrical elements. The dimensions of each element are so that it fits into cubical cell. Assembled puzzle forms a continuous pipeline that fits into cubical space, wiggling from starting element to ending element. Elements are interconnected so that groups of nine elements, belonging to one of six side surfaces of the puzzle, can be rotated about spatial axes. Each element or layer of the puzzle can be made of the same one color or different colors or gray scale levels to define puzzle difficulty. The subject puzzle requires specific imagination skills to assemble a continuous pipeline based on elements&#39; shapes and orientation. Cylindrical elements can be made hollow with opened ends so that the assembled puzzle forms a continuous tube path for an article of an appropriate size to pass through the puzzle.

Description:
FIELD OF THE INVENTION 
     This invention relates to three-dimensional puzzle toys, and in particular, to manipulable puzzles containing rotatable elements. 
     BACKGROUND OF THE INVENTION 
     The known in the art Rubik&#39;s Cube™ puzzle consists of 26 cubic elements and interior central connecting mechanism. As disclosed by Rubik in HU 170,062 and later by Sugden in U.S. Pat. No. 6,974,130 cubic elements are connected to neighbor elements or to central mechanism by cam connectors of specific shapes. Those connectors are attached to unexposed part of cubic elements. Assembled puzzle has six flat exposed outer surfaces each formed by nine surfaces of cubic elements, which are used to formulate the puzzle problem to be solved, e.g. they can carry colors, patterns, figures, symbols, signs or else. All cubic elements are connected so that any of nine elements, belonging to the same outer surface of the cube can be rotated about the axis going through the center of that surface and puzzle geometrical center. The object of the game is to restore the initial undisturbed state of the cube from its disturbed state by means of rotation of groups of nine elements. 
     Since classic 3×3×3 cube is difficult to solve for many children there were efforts in the art to change the level of difficulty. Rubik&#39;s Cube™ puzzle level of difficulty depends on number of combinations defined by total number of elements, and can be reduced as disclosed by Rubik in U.S. Pat. No. 4,378,116 for 2×3×3 cube and U.S. Pat. No. 4,378,117 for 2×2×2 cube or can be increased as disclosed by Sebesteny in U.S. Pat. No. 4,421,311 for 4×4×4 cube or by Krell in U.S. Pat. No. 4,600,199 for 5×5×5 cube. The assembly difficulty can also be reduced by increasing the number of possible solutions by means of using less colors, e.g. two- or three-color cube or cube with two-color patterns disclosed by Sugden in U.S. Pat. No. 6,974,130. In this case not all elements will have their unique position. Although reducing number of colors without changing element shape can significantly simplify Rubik&#39;s puzzle and can lead to loss of motivation. Thus there is a need for a puzzle with a motivating balance between number of elements, their colors and shapes. 
     Imagination skills required to solve Rubik&#39;s cube puzzle of all sizes and its spherical or other geometrical and stereo metrical modifications are based on outer surface color or pattern perturbation, which might be not suitable for those children or adults, who prefer spatial relationships to color ones, or for color-blind or blind people. Thus there is a need for element shape variation to develop players&#39; different imagination skills. 
     There are 3-D puzzles known in the art referenced in the present invention that use not only colors but also shapes of rotatable elements. Amusement device disclosed by Ayers in U.S. Pat. Nos. 4,708,345 and 4,881,738 used cylindrical shape of elements forming a regular polygon and rotatable about their longitudinal axis and divided into halves rotatable about axis orthogonal to polygon plane to assemble the puzzle. Those puzzles use outer surfaces as a key for puzzle problem formulation and/or solution but they do not use puzzle interior space. Thus there is a need for using of puzzle internal 3-D space to make it more entertaining and challenging and with variable level of difficulty. 
     SUMMARY OF THE INVENTION 
     A three-dimensional tube puzzle is presented in the current invention as a new modification of known 3×3×3 Rubik&#39;s cube puzzle. It consists of plurality of cylindrical elements of two main exposed shapes: straight cylinder (Coupling) and corner cylinder (Elbow). The dimensions of each element are so that it fits into a cubical cell. Assembled tube puzzle fits into cubical space. Due to spatial relationships of the disclosed 3×3×3 tube puzzle there is one cell remaining unfilled by cylindrical elements and it can be filled out by an element of exposed spherical shape. Cylindrical elements have arm-and-cam connectors that are based on modification of cam connectors disclosed by Rubik in HU 170,062 and U.S. Pat. No. 4,378,116 and by Sugden in U.S. Pat. No. 6,974,130 by means of adding extension arms of specific shapes for different types of elements. All cylindrical elements can be interconnected by those arm-and-cam connectors to neighbor elements or to puzzle interior central connecting mechanism, using the same mechanical principles disclosed by Rubik, so that any nine elements, belonging to one of six side surfaces, can be rotated about the central axis going through the central element of that one surface and through puzzle interior central mechanism. Unexposed part of each cylindrical element consists of one part, which is similar in shape to the same unexposed part of cubic element with flat surfaces in each spatial dimension formed by respective number of parallel or perpendicular edges in order to provide stable rotation of element arrays, and another part, which is modified to pyramidal shape to provide enough space for modified arm-and-cam connectors to pass through while rotation. Both modifications of either extended arm-and-cam connectors and of unexposed parts of cylindrical elements require the sizes for internal rotatable surfaces and parts for element interconnection to be reduced to fit into the space limited by central element cell. 
     There are total 26 elements forming the 3×3×3 element puzzle of the present invention: 25 elements of exposed cylindrical shape, including 16 Elbows and 9 Couplings, and one element of exposed spherical shape. 
     In its undisturbed initial state the puzzle represents a continuous pipeline structure of 3×3×3 straight and curved cylindrical elements, wiggling from its starting element to its ending element inside cubical space. The puzzle is solved when the whole pipeline is assembled from its disturbed state. The game can be played in a competitive way measuring a progress by time or by number of moves spent to solve the puzzle completely. 
     In order to vary the level of puzzle difficulty all cylindrical elements can be the same one color or transparent. In this case element shape and orientation will be the main criteria to solve the puzzle. Although not all elements will have their unique positions, which will increase the number of puzzle possible solutions and will lower the level of difficulty. Such version of the present invention puzzle can be designed as an entry level tube puzzle for children younger than 8 years old (a recommended age for Rubik&#39;s cube) or for blind children and adults. The next level of difficulty can be designed using three colors, e.g. one for each of three layers of the tube puzzle. The number of possible solutions will be reduced compare to single-color version, because there will be three different groups of elements belonging to respective layers and each group should be assembled as a continuous pipeline using the shape and orientation criteria. This three-color tube puzzle can be designed as three-gray-scale-level version friendly for color-blind children and adults, e.g. Black-White-Gray. A multi-colored version of the disclosed tube puzzle can be designed in such a way that each cylindrical element has different color and all 25 elements represent a sequence color equivalent to discrete rainbow spectrum, i.e. from “infra-red” at starting point to “ultra-violet” at ending point, when each element color matches preceding and subsequent element colors in an undisturbed state of said puzzle, e.g. Dark Blue-Blue-Light Blue, and a container element can be white or black. In such version each cylindrical element will have a unique position and there will be only one solution for the disclosed tube puzzle as it is for classic Rubik&#39;s puzzle with the same level of difficulty but with additional stimulation of pipeline assembly. The disclosed tube puzzle can be also designed as a full gray-scale version when 25 cylindrical elements represent sequential levels of gray scale from black at starting point to white at ending point, and container element can be designed with a pattern. Those multi-colored or full gray-scale versions also introduce an encouraging opportunity for younger children: first to assemble the whole pipeline without matching colors or gray-scale levels for training and entertainment and for releasing a hidden article, and then to try to assemble the puzzle with all colors or gray-scale levels matched. Cylindrical elements also can be numbered or patterned or can have any signs or symbols to form a predefined logical sequence of the elements. 
     Each tube element can be made of plastic or other synthetic material of appropriate color using injection-molding technology. All cylindrical elements and their arm-and-cam connectors can be produced hollow in order to save material. The ends of each cylindrical element can be made opened. In this case the interior of the solved puzzle can represent a tube path and an article, e.g. ball, of appropriate size that can be put through the puzzle from its entry point at its top layer to its exit point at its bottom layer (or visa-versa). The element with exposed spherical shape can be designed as a Container element with detachable cap to keep an article and can be positioned in the center of puzzle side with ending point. 
     As described above, the disclosed in present invention three-dimensional tube puzzle stimulates player&#39;s spatial imagination skills to assemble a continuous pipeline structure using shape and orientation criteria and if designed colors or gray-scale levels or patterns or other signs or symbols. The disclosed tube puzzle uses its internal 3-D space and provides additional motivation and amusement features compare to puzzles with rotatable elements previously known in the art that use outer surfaces. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  represents three-dimensional tube puzzle in assembled state made in accordance with the preferred embodiment of the present invention; 
         FIG. 2  shows views of six side surfaces of 3×3×3 tube puzzle: A—top, B—front, C—bottom, D—left, E—right, F—back; 
         FIG. 3  represents views of cylindrical elements belonging to the first sub-group of the first group; 
         FIG. 4  represents views of cylindrical elements belonging to the second sub-group of the first group; 
         FIG. 5  represents views of cylindrical element belonging to the third sub-group of the first group; 
         FIG. 6  represents views of cylindrical elements belonging to the first sub-group of the second group; 
         FIG. 7  represents views of cylindrical elements belonging to the second sub-group of the second group; 
         FIG. 8  represents views of cylindrical elements belonging to the third sub-group of the second group; 
         FIG. 9  represents views of cylindrical elements belonging to the first sub-group of the third group; 
         FIG. 10  represents views of cylindrical elements belonging to the second sub-group of the third group; 
         FIG. 11  shows views of unexposed sides of the assembled tube puzzle: A—without top layer, B—without two upper layers; 
         FIG. 12  shows side view of three-gray-scale-level tube puzzle. 
         FIG. 13  shows all types of hollow elements of the tube puzzle in isometric views. 
         FIG. 14  represents three-dimensional tube puzzle in assembled state consisted of hollow elements in accordance with the embodiment of the present invention; 
         FIG. 15  shows top views of horizontal cross-sections of the tube puzzle layers along the central lines t-t, m-m and b-b in  FIG. 2B : A—top layer along the line t-t, B—middle layer along the line m-m, C—bottom layer along the line b-b; 
         FIG. 16  shows side views of vertical cross-sections of the tube puzzle along the central lines u-s and v-w in  FIG. 2A ; 
         FIG. 17  shows views of six side surfaces of 4×4×4 tube puzzle: A—top, B—front, C—bottom, D—left, E—right, F—back; 
         FIG. 18  shows views of six side surfaces of 5×5×5 tube puzzle: A—top, B—front, C—bottom, D—left, E—right, F—back. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 ,  2 ,  11  and  12 , illustrated therein is a three-dimensional tube puzzle  10  made in accordance with a preferred embodiment of the present invention. 
       FIG. 1  shows a volumetric view of assembled tube puzzle  10 , consisting of 26 elements, connected so that an array of any 9 elements, belonging to the same side surface of the puzzle, can be rotated about one of spatial axes X, Y, Z. The dimensions of each cylindrical element are so that it fits into cubical cell with suggested characteristic edge equal to about 1 inch, so that suggested characteristic dimensions of the tube puzzle can be equal to 3″×3″×3″. An article  12  of the size smaller than internal tube diameter can be put though the puzzle from its entry point  14  and released at its exit point  16 . Other numbers designate different type of tube elements disclosed in the present invention. 
     Six side surfaces of the disclosed puzzle  10  are shown on  FIGS. 2A-2F : A—top, B—front, C—bottom, D—left, E—right, F—back. Puzzle layers can be identified as: Top, Middle and Bottom, as indicated by lines t-t, m-m and b-b respectively in  FIG. 2B . Hereinafter the numbers designate fully visible elements, e.g.  30 , and numbers with apostrophe sign designate partly visible elements, e.g.  30 ′. 
       FIGS. 3-10  represent volumetric and plane views of cylindrical elements that are divided into three main groups based on their spatial position, exposed shape and type of connectors. 
       FIGS. 3-5  represent the first group of six cylindrical elements that are positioned in the center of each of six puzzle side surfaces and are rotatable in one plane. Those six elements have identical unexposed surfaces and arm connectors to be connected to the central connecting mechanism but are divided into 3 sub-groups based on their exposed shape and orientation.  FIG. 3  shows the sub-group of four Couplings  30 .  FIG. 3A  is a volumetric view,  FIG. 3B  is a backside view and  FIG. 3C  is a side view of central Coupling element. Exposed surface of that hollow Coupling has cylindrical shape and its unexposed surface has complex shape formed by cubic basement with four identical parallel edges  32   a - d  that are cut-off at 45 degrees from each of four sides forming a shape of pyramid with four identical edges  33   a - d  that provide enough space for passing of neighbor and corner elements connector arms. Top of that pyramid is cut-off by a crossing of four spherical surfaces with four identical edges  35   a - d  that provide smooth sliding of cam connectors of an array of neighbor elements in a respective plane of rotation. On top of that multi-spherical surface there is a cylindrical arm connector  34  that connects to puzzle central connecting element following the same mechanics disclosed by Rubik in HU 170,062. Cubic part creates flat side surfaces to stabilize sliding motion of neighbor element arrays while rotation. 
       FIG. 4  represents the fifth central element  40 , which can be used as a Container for an article  12 .  FIG. 4A  shows a volumetric view,  FIG. 4B  shows back view and  FIG. 4C  shows bottom view of central Container element exposed surface. Unexposed surface of Container  42  has the same complex shape as Coupling central element, i.e. it has: a cubic part with four identical edges  42   a - d  and four identical edges  47   a - d  and a pyramid part with four identical edges  43   a - d , which is cut-off by a crossing of four spherical surfaces forming four identical edges  45   a - d , and a cylindrical arm connector  44 . The exposed surface of Container  42  is shown in  FIG. 4C  and is formed by semi-spherical detachable cap  46 , as shown on  FIG. 4B , and by visible four corners of Container cubic part formed by edges  47   a - d . The Container element  40  is designed to fill out the remaining empty 26 th  cell, which cannot be filled by any cylindrical element due to spatial relationships of the tube puzzle  10  disclosed in present invention. 
       FIG. 5  represents the sixth central Elbow element  50 .  FIG. 5A  shows a volumetric view,  FIG. 5B  shows right side view,  FIG. 5C  shows backside view,  FIG. 5D  shows topside view (unexposed surface) and  FIG. 5E  shows bottom side view (exposed surface) of central Elbow element. Unexposed surface of Elbow  50  has the same complex shape as Coupling and Container central elements, i.e. it has: a cubic part with four identical edges  52   a - d  and two identical edges  57   a, b  and a pyramid part with four identical edges  53   a - d . The pyramid part is cut-off by a crossing of four spherical surfaces with four identical edges  55   a - d . A cylindrical arm connector  54  is on top of that multi-spherical crossing surface. The exposed surface of Elbow  50  is shown in  FIG. 5E  and is formed by corner element arc  59  and by visible corner of cubical part with edges  57   a, b . The role of cubic part of each central element described above is to block visibility of internal central connector and intrusion of any objects inside puzzle to prevent its damage. 
       FIGS. 6-8  represent the second group of twelve cylindrical elements that are positioned in the middle of each edge formed by any two side surfaces of the present puzzle and are rotatable in two perpendicular planes. Those twelve elements have identical arm-and-cam connectors with cam part having a shape of square cuboids but are divided into 3 sub-groups based on their exposed shape and orientation.  FIG. 6  represents the first sub-group of five mid-Couplings  60 .  FIG. 6A  shows volumetric view,  FIG. 6B  shows front view and  FIG. 6C  shows side view of mid-Coupling  60 . The exposed part of mid-Coupling  60  has cylindrical shape and its unexposed part is formed by a crossing of two flat surfaces with edges  62   a, b  and  62   c, d . The edge formed by a crossing of those two flat surfaces is not exposed because its both corners are cut-off at 45 degrees to each spatial axis forming two flat triangular surfaces  66   a, b  that provide enough or the arms of neighbor elements&#39; connectors. Between those two triangles there is an attached arm-and-cam connector  64 , which has an extension arm  64   a  ended with a cam  64   b . Arm-and-cam connectors have two functions: to keep mid-Coupling elements between two central elements shown in  FIGS. 3-5  and to receive and hold cam connectors of neighbor corner elements shown in  FIGS. 9-10  by its flat surfaces  64   c  with bordering part formed by a fragment of cylindrical surface  64   d.    
       FIG. 7  represents the second sub-group of three mid-Elbows  70 .  FIG. 7A  shows volumetric view,  FIG. 7B  shows front view and  FIG. 7C  shows top view of cylindrical element  70  with arm-and-cam connector  74 , which has the same structure and respective features  74   a - d  as connector  64  but is attached to the center of the edge located between two ends of the cylindrical element. There are two identical flat surfaces at the top  70   a  and the bottom of element  70  with edges  72   a, b  and  72   c, d  respectively limited by arc  70   b  going along the central axis of curved cylindrical element. Two corners adjacent to connector  74  are cut-off at 45 degrees to each of spatial axis forming two flat triangular surfaces  76   a, b  to provide enough space for the arms of neighbor corner elements&#39; connector. 
       FIG. 8  represents the third sub-group of four mid-Elbows including one Elbow  80  and three Elbows  88 .  FIG. 8A  shows volumetric view,  FIG. 8B  shows top view,  FIG. 8C  shows left side view,  FIG. 8D  shows front view and  FIG. 8E  shows right side view of mid-Elbow  80  with arm-and-cam connector  84 . Connector  84  has the same structure and respective features  84   a ,  84   b ,  84   c ,  84   d  as connectors  64  and  74  described above. Connector  84  is attached to one end of element  80  at the center of the edge formed by two perpendicular planes: a flat surface  86  with edges  86   a ,  86   b  and  86   c  and a plane going through that end of cylindrical element  80 . Two corners adjacent to connector  84  at both sides are cut-off at 45 degrees to each of spatial axis forming flat triangular surfaces  82   a, b  to provide enough space for the arm of neighbor corner elements&#39; connectors. Another three mid-Elbows  88  are exact minor reflected copies of element  80 , as shown in  FIG. 8F . 
       FIGS. 9-10  represent the third group of eight corner cylindrical elements that are positioned in the corners of the puzzle disclosed in present invention and are rotatable in three planes about spatial axes. Those corner-Elbows have identical shape of arm-and-cam connectors and are divided into 2 sub-groups based on their orientation, function and unexposed shape.  FIG. 9  represents the first sub-group of six corner-Elbows  90 .  FIG. 9A  shows volumetric view,  FIG. 9B  shows front view,  FIG. 9C  shows top view and  FIG. 9D  shows bottom view of corner-Elbow  90 . The unexposed part of corner-Elbow has a shape of cube corner formed by three edges  92   a - c  with attached cylindrical arm  94  ending with cam connector  96 . Cam connector  96  has an approximate shape of ellipsis-quarter cut-off by surfaces of three types  96   a ,  96   b  and  96   c  similar to the one disclosed by Rubik and later by Sugden and fits into 3-D space limited by cuboid cam connectors of neighbor cylindrical elements and spherical surfaces of central cylindrical elements  30 ,  40  and  50 . As shown in  FIG. 9D  element  90  has flat surface  90   a  at the bottom side limited by arc  90   b  going along the central axis of curved cylindrical element. 
       FIG. 10  represents the second sub-group of two minor reflected corner-Elbows  100  and  110  that serve as starting and ending elements of the puzzle.  FIG. 10A  shows volumetric view,  FIG. 10B  shows front view,  FIG. 10C  shows top view and  FIG. 10D  shows bottom view of entry point corner-Elbow  100 . Unexposed part of cylindrical element  100  has a shape of cube corner formed by edges  102   a - c  and arc edges  100   b  and  100   d  with respective flat surfaces  100   a  and  100   c . A cylindrical arm  104  is attached to the unexposed corner of Elbow  100  ending with cam connector  106  identical to cam connector  96  described above.  FIG. 10E  shows bottom view of exit point corner-Elbow  110 , which is mirror reflected copy of element  100 . It has the similar flat surfaces at unexposed sides, and surface  110   c  is located between edges  112   a,b  and arc edge  110   d.    
       FIG. 11  shows two views of unexposed sides of the assembled tube puzzle.  FIG. 11A  shows a top view of assembled Middle layer with removed Top layer of the puzzle. Arm connectors  34  and  54  of central tube elements  30  and  50  are connected to the central connecting mechanism  20  based on the same mechanical principles disclosed by Rubik in HU 170,062. Corner mid-Elbows  70  and  80  are inserted between neighbor central elements  30  and  50  so that arm-and-cam connectors  74  and  84  keep them attached to central elements forming the Middle layer. Tube elements&#39; unexposed surfaces can be made flat, as marked by shaded gray areas  30   a ,  50   a ,  70   a  and  80   a  in order to stabilize sliding motion of element arrays while rotation. 
       FIG. 11B  shows view of unexposed side of assembled puzzle Bottom layer with removed two upper layers. Square cuboid shape connectors  64  of mid-elements  60  and  88  receive Cam connectors  96  of corner tube elements  90  and  110 . Arm connector  44  of Container element  40  is located in the center and when connected to the central connecting mechanism keeps the Bottom layer attached to the Middle layer. Flat surfaces  60   a ,  88   a ,  90   a  and  110   a  provide stable rotation of element arrays and are shaded by gray color. 
     Cubical parts of all elements of the present puzzle not only stabilize the sliding motion of element arrays but they block visibility of element unexposed internal sides with arm-and-cam connectors and cut-offs except some features of Elbow elements such as flattened surfaces of elements  80 ,  100  and  110  or corners of elements  40  and  50 . 
       FIG. 12  shows front view (similar to one shown in  FIG. 2B ) of three-gray-scale-level puzzle. Top layer of the puzzle has gray color, Middle layer is white and Bottom layer is black. 
       FIGS. 13A-13H  show all types of hollow elements of the tube puzzle in isometric views that correspond respectively to cylindrical elements shown on  FIGS. 3-10 : A—to  FIG. 3A , B—to  FIG. 4A , C—to  FIG. 5A , D—to  FIG. 6A , E—to  FIG. 7A , F—to  FIG. 8A , G—to  FIG. 9A , H—to  FIG. 10A . 
       FIG. 14  shows a volumetric view of assembled tube puzzle  11 , which is similar to one shown in  FIG. 1  but consisting of hollow elements shown in  FIG. 13 . An article  12  of size smaller than internal tube diameter can be put though the puzzle from its entry point  14  and released at its exit point  16 . 
       FIG. 15  represents three cross-sections of disclosed puzzle layers.  FIG. 15A  shows cross-section of the Top layer of puzzle  11  along the line t-t in  FIG. 2B  viewed from top. Assembled Top layer forms a continuous pipeline way for an article  12  beginning with entry point corner-Elbow  100  and ending with corner-Elbow  90 , which provides transition to the lower Middle layer.  FIG. 15B  shows cross-section of the Middle layer of puzzle  11  along the line m-m in  FIG. 2B  viewed from top. Assembled Middle layer forms a continuous pipeline way for an article  12  beginning with corner-Elbow  80  and ending with central Elbow  50 , which provides transition to the lower Bottom layer. Central connecting mechanism  20  is connected to central Couplings  30  and central Elbow  50  based on the same mechanics  22  disclosed by Rubik in HU 170,062.  FIG. 15C  shows cross-section of the Bottom layer of puzzle  11  along the line b-b in  FIG. 2B  viewed from top. Assembled Bottom layer forms a continuous pipeline way for an article  12  beginning with mid-Elbow  88  and ending by exit point corner-Elbow  110 . The central element is presented by Container  40  without cap  46  shown in  FIG. 4 . 
       FIG. 16  represents two cross-sections of the puzzle along two perpendicular planes.  FIG. 16A  shows central cross-section of the puzzle along the line u-s in  FIG. 2A  viewed from point w.  FIG. 16B  shows central cross-section of the puzzle along the line v-w in  FIG. 2A  viewed from point s. Central tube elements  30 ,  40  and  50  are connected to central connecting element  20  using the same mechanics  22  disclosed by Rubik in HU 170,062. Tube elements  60 ,  80 ,  88 ,  90  and  100  are kept between central elements by their arm-and-cam connectors. 
     As described above, several critical modifications were made for unexposed element parts and connectors disclosed by Rubik, Sugden and other cited patents in order to provide feasibility and functionality of the tube puzzle disclosed in the present invention. Exposed element cylindrical shapes required providing an internal unexposed flat side surfaces to stabilize sliding motion while element rotation and to hide puzzle interior. Those flat surfaces required a reduction of the puzzle internal space used for element interconnection. The latter required in turn cam connectors to be extended with arms of specific shapes for different elements. Further modification was made by pyramidal cut-offs of provided internal unexposed flat side surfaces of cylindrical elements in order to provide enough space for connectors&#39; extension arms to pass through while element rotation. Puzzle internal space used for element interconnection can be reduced up to single element space in order to provide maximal stability of rotation and maximal diameter of internal tube path in case of hollow cylindrical elements. All described modifications are shown in  FIGS. 3-11 ,  13 ,  15 - 16  and resulted in seven types of elements with exposed straight and curved cylindrical shapes and one element with exposed spherical shape required to form the 3×3×3 tube puzzle disclosed in the present invention. Instead only three types of elements are required to form a 3×3×3 cube puzzle known in the art. 
     The disclosed in the present invention 3×3×3 tube puzzle can be extended to 4×4×4 tube puzzle as shown in  FIG. 17  or to 5×5×5 tube puzzle as shown in  FIG. 18  based on the same principle of extension arms for connectors and providing flat surfaces for unexposed parts of cylindrical elements disclosed in the present invention and following mechanical principles disclosed by Sebesteny in U.S. Pat. No. 4,421,311 and by Krell in U.S. Pat. No. 4,600,199 respectively for element interconnection. In 4×4×4 extended version of tube puzzle a container element with exposed spherical shape is optional since all cells of the puzzle can be filled out by tube elements. Extended 4×4×4 or 5×5×5 tube puzzle elements can be hollow and can be the same one color or transparent or can be respectively 4 or 5 gray scale levels belonging to each of 4 or 5 puzzle layers respectively or can represent a sequence of colors equivalent to discrete rainbow spectrum analogically to described above 3×3×3 tube puzzle. 
     All elements&#39; and connectors&#39; dimensions and shapes disclosed in the present invention are shown to reveal the principal structure, features and functioning of the tube puzzle and can be adjusted and slightly rounded during injection molding manufacture process in order to provide smooth and stable rotation of tube element arrays. Configuration of continuous pipeline in initial state of tube puzzle of any size can be produced variable. Arm-and-cam connectors can be maid hollow in order to save material. 
     The disclosed tube puzzle and an article can be designed in a form of identifiable objects, creatures or characters to resemble an identifiable environment, e.g. a tunnel structure with a racing car or a snake swallowing a prey or any other. 
     While the above is a complete description and illustration of the preferred embodiment of the present invention, it is possible to use various alternatives, modifications and equivalents. Therefore, the scope of the present invention should be determined not with reference to the above description but should, instead, be determined with reference to the appended claims, along with their full scope of equivalents. In the claims that follow, the indefinite article “A”, or “An” refers to a quantity of one or more of the item following the article, except where expressly stated otherwise. The appended claims are not to be interpreted as including means-plus-function limitations, unless such a limitation is explicitly recited in a given claim using the phrase “means for.”