Patent Publication Number: US-6705740-B1

Title: Tracking mirror

Description:
This application is based on my U.S. Provisional Patent Application No. 06/146,040, TRACKING MIRROR, filed Jul. 28, 1999, from which I claim priority. 
    
    
     This Invention is based on my previous work expressed in U.S. Pat. No. 4,971,312, ILLUSION APPARATUS, U.S. Pat. No. 5,681,223, TRAINING VIDEO METHOD AND DISPLAY, and, particularly, U.S. Pat. No. 5,871,404, OPTICAL BLOB, the contents of each being here incorporated by reference thereto. 
     BACKGROUND 
     The Tracking Mirror is preferably used in place of typical security mirrors commonly used in retail stores to catch shoplifters. Security mirrors are convex, to allow wide angle coverage, and are generally mounted near or on the store&#39;s ceiling, to provide unobstructed aerial views. Commonly, store personnel monitor the premises by occasional glances at the mirrors. Security mirrors are often semi-transparent (i.e., with reflective coating thin enough to allow some light to pass through) to allow video cameras or security personnel to carry out hidden surveillance from behind the mirrors. 
     In most cases it is unlikely that security personnel are peering down through a mirror. It is also unlikely that a video camera will at any moment be properly positioned to catch a shoplifter in the act and, even if a camera sees the act, security personnel may not be monitoring that camera at that time. A potential shoplifter will, however, check reflections in the security mirrors to see if personnel in the store are watching him/her. 
     GENERAL DESCRIPTION 
     It is a purpose of this Invention to deter theft (and/or other crimes) by adding an additional factor of intimidation to dissuade potential shoplifters from becoming “kinetic” shoplifters. Under the preferred embodiment, when a potential shoplifter looks up to check a security mirror (to see if store personnel are watching), he/she sees a red circle about his/her own reflection in the mirror. 
     The Invention appears in a preferred embodiment for each of the two commonly known security mirror types. 
    
    
     DESCRIPTIONS OF THE FIGURES 
     FIG. 1 is a side section through the centerline of the mirror and conical housing of the first preferred embodiment. 
     FIG. 2A is a side section through a lamp housing attached to the conical housing of FIG. 1 
     FIG. 2B is a front elevation showing the preferred red circle in a transparency. 
     FIG. 3 is a side section through a light catcher attached to the conical housing of FIG.  1 . 
     FIG. 4 is a side section through a wide-angle light catcher attached to the conical housing of FIG.  1 . 
     FIG. 5 is a side section through a perforated convex mirror. 
     FIG. 6 is a side section through the centerline of the hemispherical mirror (with a lamp housing) of the second preferred embodiment. 
     FIG. 7A is a section through the centerline of the transparent globe of the second preferred embodiment. The right side of the figure shows a typical meridian; the left side shows a typical parallel. 
     FIG. 7B shows the meridians of FIG. 7A projected to an elevation. 
     FIG. 7C is a detail section through a masked groove in the transparent globe of the second preferred embodiment. 
     FIG. 7D shows the parallels of FIG. 7A projected to an inverted plan view. 
     FIG. 8A is a plan section through the equator of an alternative globe for the second preferred embodiment. 
     FIG. 8B is an elevation of the visible pattern of the alternative globe of FIG.  8 A. 
     FIG. 9A is a side section through the spinning ring of an alternative to the second preferred embodiment. 
     FIG. 9B is a plan section through one side of the ring of FIG.  9 A. 
     FIG. 9C is an alternative to the embodiment shown in FIG.  9 B. 
     FIG. 10 is an isometric drawing of an alternative to the illuminated object of the second preferred embodiment. 
     FIG. 11A is a front elevation of the turning disk used in an enhancement to the first preferred embodiment. 
     FIG. 11B is a front elevation of the spinning disk used in an enhancement to the first preferred embodiment or an alternative in the second preferred embodiment. 
     FIG. 11C is a side section of one embodiment of the disk of FIG.  11 B. 
     FIG. 12 shows a moiré version of the circle of the first preferred embodiment. 
     FIG. 13 is a side section through the centerline of an alternative transparent globe of the second preferred embodiment. The left side of the figure shows a surface pattern; the right side shows an etched pattern. 
    
    
     FIRST PREFERRED EMBODIMENT 
     The first preferred embodiment  100  incorporates a shallow (preferably about 30-60 degrees of a sphere) convex mirror  110 . 
     A security mirror of this type is generally not partially transparent, as required in the Invention, but is an ordinary convex mirror mounted in a circular channel frame with backing of, typically, masonite. The masonite is mounted in turn to an arm with, typically, a ball and socket joint for adjustment. The arm terminates at a mounting bracket so that it may be attached to a wall or ceiling. 
     In the preferred embodiment for this type of security mirror, a typical mirror blank is coated with a reduced amount of silvering (typically aluminum), as is known in the art, to create partially transparent mirror  110 . Roughly equal reflection and transmission are useful, but, where brightly lit spaces allow, lighter silvering is preferred. In any case, the Invention tolerates a rather wide range of silvering. 
     Typical circular channel frame  120  is used, without the masonite, to mount mirror  110  to a preferably conical housing  130 . Conical housing  130 , its large end being slightly smaller than the mirror  110 , engages the frame with flange  135 , flange  135  matching the diameter of mirror  110 . Flange  135  may be discontinuous. 
     Conical housing  130  may be of any durable material such as blow molded plastic or galvanized sheet steel. The inside of conical housing  130  is preferably matte black; the outside is preferably a neutral color so as to minimize its apparent size. 
     Typical mounting arm assembly  140  is attached, not to the (no longer present) masonite backing, but to the wall of conical housing  130 . Conical housing  130  provides for minimum restriction in mirror mounting position and orientation. 
     Conical housing  130  is preferably truncated at a plane coincident with center of curvature C of convex mirror  110 . At that distance, the small end of conical housing  130  is preferably about a quarter the diameter of mirror  110 . 
     To the small end of conical housing  130  is mounted, by ordinary means, lamp housing  200 , containing lamp or lamps  210 . Lamp  210  may be of any type. Transformers, batteries, ballasts, etc. (as needed) may be contained within or attached to lamp housing  200  or placed elsewhere. Lamp housing  200  may be vented. 
     A transparency  270  (or translucent image) of a circle  250  (preferably red with a black center and a black frame) is mounted in the front of lamp housing  200  (the side toward conical housing  130 ). Where a red transparency  270  is used, the inside of lamp housing  200  is preferably white. A clear transparency  270  can be used to display a red circle if the interior of lamp housing  200  is red or if lamps  210  are red. 
     Preferred for economy, particularly for use with this first preferred embodiment, and particularly for use in brightly lit stores (where mirror silvering can be particularly thin), is light catcher  300  in place of lamp housing  200 . Basically a scoop (as shown in FIG.  3 ), white inside or mirrored, light catcher  300  can be positioned beneath a ceiling fixture or anywhere under a generally illuminated ceiling. Even though an upward opening scoop is preferred, light catcher  300  can be open, or transparent or translucent in other or all directions (as shown in FIG.  4 ). 
     It may be preferable, in a light catcher embodiment, to modify the color of the otherwise preferably red circle  250 , perhaps even tolwhite, in order to take fuller advantage of the ambient light. 
     The lamp housing  200  or light catcher  300  may be adjustably mounted. Adjustments parallel to the mirror can be used to more precisely position red circle  250 , preferably concentric with the center of curvature C of mirror  110 . 
     Adjustment toward mirror  110  will cause red circle  250  to lag behind as the viewer&#39;s image moves away from the center of mirror  110 . Adjustment away from mirror  110  will cause red circle  250  to lead the viewer&#39;s image as the image moves away from the center of mirror  110 . Such adjustment may be used intentionally for beneficial effects in some embodiments of the Invention or in other embodiments of the Patents incorporated herein. 
     In a preferred embodiment, lamp housing  200  or light catcher  300  is preferably red inside and has a circular aperture (preferably about one sixth the mirror diameter) facing the mirror. Preferably metal disk  350  is supported on bracket  320 , hidden behind (i.e. on the lighted side of) itself. Disk  350  is preferably black on the side facing mirror  110  and red on the back side. Bracket  320  is preferably red. 
     Disk  350  is smaller in diameter than housing  130  at that point so that a bright red ring around it is visible through mirror  110 . Metal disk  350  will be more durable and heat tolerant than the alternative transparency. 
     Also for durability, and for harsh or hazardous locations, the mirror itself may be formed from polished metal such as stainless steel, well known in some security mirror products. It is however required that the mirror be partially transparent. The mirror  111  is, therefore, formed from perforated stock or may be perforated as part of the forming process (by punching) or after forming (as by drilling). 
     Such a mirror  111  can be painted (or otherwise finished) matte black on its concave side to suppress unwanted reflections. This is a valuable structure for many uses of the diverse embodiments of the present Invention and of the other Patents incorporated herein by reference. Not only are miscellaneous reflections suppressed, but the ability of the concave side to focus collimated light is obviated. Mirrors of diverse materials can be manufactured by ordinary means to take advantage of these benefits of perforated mirrors. 
     SECOND PREFERRED EMBODIMENT 
     The second preferred embodiment  400  incorporates a hemispherical (or essentially hemispherical) mirror  410 . 
     A security mirror of this type is generally dropped through a hung ceiling and may be partially transparent, particularly for video surveillance through the mirror. 
     This type of mirror does not require the conical housing of the first preferred embodiment. Because the center of curvature C is roughly equivalent to the back edge of the mirror  410 , a simple flat cover  420  is preferred. Cover  420  has a central aperture, but generally prevents stray light (from above the ceiling) from entering the mirror. 
     At the center of cover  420  is mounted lamp housing  500 , similar to that in the first preferred embodiment. Horizontal hanger bar  430  is preferably provided to straddle the back edge of mirror  410  (above flat cover  420 ) so that flat cover  420  need not support lamp housing  500 . 
     If the viewer moves far off the mirror&#39;s axis, two problems can appear. First, red circle  250  begins to appear more and more elliptical. Second, commercial mirror domes tend to have less accurate curvature away from the axis. 
     Fortunately, however, people walk on the floor and security mirrors are mounted at the ceiling. For that reason, the periphery of hemispherical mirror  410  is not used and an additional concentric area is active only for very distant viewers. Furthermore, hemispherical mirrors substantially reduce the size of images of the distant viewers. 
     For example, a six foot tall viewer, fifty feet from an eighteen inch radius dome mounted to a twelve foot ceiling, will see his/her image about 83 degrees off the axis of the mirror. However the image will be only about an inch tall, fairly indistinguishable at that distance. Moving in to twenty-five feet, the same viewer will see his/her two inch tall image about 77 degrees off the mirror axis. At twelve feet, the image will be about four and a quarter inches tall at about 63 degrees off the mirror axis. Figures for the same conditions with a twelve inch radius mirror are three quarters of an inch at 83 degrees, an inch and three eighths at 77 degrees and two and three quarter inches at 63 degrees. 
     These numbers are good enough to avoid problems due to mirror curvature, but red circle  250  may come to appear undesirably elliptical which would tend to reveal that red circle  250  is not actively tracking the viewer. 
     Therefore, lamp housing  200  of the first preferred embodiment  100  must be modified to protect the illusion. Lamp housing  500  of the second preferred embodiment  400  preferably has, protruding from it, hollow transparent globe  510 . The purpose and structure of hollow transparent globe  510  are described below. 
     Red Circles 
     It is important to recognize that a red circle is preferred, not mandatory. A circle is preferred for security mirrors to very definitely define the viewer&#39;s position while leaving a clear image of the viewer. Red is preferred as I believe it to be more intimidating for this purpose than other colors. Red is, however, more subtle than, say, adding crosshairs to the circle. 
     Additionally, the circle carries no meaningful size or other information to help the viewer distinguish the actual position of the circle in space. And the circle, although actually behind the viewer&#39;s image, interferes as if it were in front. That, and the compelling connection between a picture (the viewer&#39;s image) and its frame, all lend to the impression that the red circle is actively tracking the viewer. 
     Some of what follows is more useful or preferable in either the first preferred embodiment  100  or second preferred embodiment  400  or in other embodiments of the Invention or in other embodiments of the Patents incorporated herein. 
     The problem of the red circle appearing elliptical, with mirrors of the second preferred embodiment  400 , can be solved in different ways according to the requirements of the moment. 
     For the reasons stated above, a red circle is still the preferred image for both preferred security mirror embodiments. Furthermore, a red circle is easy to use in the first preferred embodiment  100  and it may be preferable to maintain the same image across a line of products incorporating both preferred embodiments. 
     A bright spherical object, at the center of curvature of the mirror, will appear through the mirror as a disk, regardless of the point of view. But a disk of light is not a circle and, although effective in tracking, will wash out the image of the viewer. To form the image of a circle, the center of the disk must be obscured. That would be easy if only one point of view was being addressed. But the disk is actually a sphere and the center must be obscured from any point of view, with the periphery, preferably always, remaining bright. 
     Preferably, hollow transparent globe  510  is positioned about the center of curvature C of mirror  410 . Globe  510 , which may be clear or tinted (preferably red), has an aperture at the top that is preferably formed by (or as if) cutting the globe horizontally. The top edge of globe  510  will, therefore, be flat. Flat edge  515  is then conveniently illuminated, preferably through a ring shaped aperture, from lamp housing  500  or a light catcher  300 . 
     Alternatively globe  510  may be formed with neck  530  at the top, neck  530  terminating in a flat, circular surface  515 . If neck  530  is incorporated it must be integral with globe  510  and the transition between the cylindrical shape of neck  530  and the spherical shape of globe  510  must be well faired (to avoid light leakage). 
     Since globe  510  is transparent, light is held within the globe wall by internal reflection and very little light is emitted from its inner or outer surface, except at flat top edge  515 . To obscure top edge  515  from view from below, black disk  525  can be positioned inside the top edge of globe  510 . It is preferred, however, to obscure the entire inner surface of globe  510 , which may be accomplished by, e.g., filling globe  510  with a black foam ball or painting the inside black. 
     To make globe  510  appear, from any point of view, as a bright circle, globe  510  is scored or grooved or drilled or etched (by ordinary means). The scoring, grooving, drilling, or etching pattern may be a multiplicity of (preferably equally spaced) meridians  535 . Internal reflection in the globe wall will thereby be disturbed and, as is well known in the art, meridians  535  will emit light. As dictated by well-known principles of geometry (and as shown in FIG.  7 B), meridians  535  will appear, when viewed generally horizontally, close together at the perceived edges of globe  510  and farther apart near the center. 
     It is preferred that each meridian  535  be obscured by a black mask  545  or painted over on the outside surface of the globe. Black mask  545  is broader than the underlying meridian  535  to obscure meridian  535  from a reasonably wide angle (about 60 degrees). Thus meridians  535  near the center of any generally horizontal view of the globe will be invisible through mirror  410 . Those at the edge of any horizontal view of globe  510  will not only appear, but will appear close together as a bright ring. 
     It is sometimes (as when space under mirror  410  is not accessible or when another mirror  410  “watches” the space) not necessary to accommodate views from the underside of mirror  410 . However, if desired, parallels  555  can also be added to the pattern to extend the illusion to all points of view. If parallels  555  are added, it is preferred to mask each parallel  555  with a ring  565 . Each ring  565  is preferably cylindrical, rather than conical, to obscure generally horizontal views of the associated parallel  555  while leaving parallel  555  visible to a viewer below. The series of parallels  555  is preferably terminated shortly north of the equator of the globe  510 , where the parallels  555  are no longer visible, through the wall of globe  510 , from below. 
     Meridians  535  and parallels  555  described above are preferred for some uses. A pattern that accomplishes a similar result with more consistent coverage from many angles is more generally preferred. The more generally preferred pattern can also be formed by scoring, grooving, drilling, or etching. 
     The more generally preferred pattern, actually a very large class of patterns, is a somewhat uniform, relatively fine (to appear, from a distance, to be essentially continuous) pattern, which may be a grid or dot pattern or a random stipple. The elements of the pattern preferably cover about fifty percent of the surface area of globe  510 . The pattern is then masked so it cannot be seen directly on the outside of globe  510 , but only through the opposite surface of globe  510 . The center of globe  510  being opaque, the generally illuminated surface of globe  510  thus appears as a bright circle. 
     Although not quite as bright (with similar illumination) as the scored, grooved, or etched globe, it is often preferred, particularly for economy, to use a smooth surfaced (i.e. not scored, grooved, drilled, or etched) transparent globe  510  and to apply paint or ink  560  of a light shade to take the place of the scoring, grooving, drilling, or etching. Where paint or ink  560  is applied, it will disturb the internal reflection in the transparent globe  510  and light will escape from the globe&#39;s surface. 
     A particular advantage of this approach is that the illuminated pattern, being essentially two-dimensional, can be masked by an essentially congruent dark pattern, rather than a dark pattern with larger elements (necessary to cover disparate viewing angles in more three-dimensional patterns). 
     Paint or ink  560  can be applied by any ordinary means such as manual brush painting, spraying, or silkscreen. White or red paint or ink  560  is preferred for the reasons discussed above. The pattern may be regular or irregular, but (although not absolutely necessary, because the outside surface of the pattern is not directly illuminated) should be covered with a congruent pattern of preferably matte black paint or ink  565 . The congruent pattern of dark paint or ink  565  can be created either by controlling the placement of the paint or ink, as in stenciling or silkscreen, or by allowing dark paint or ink  565  to adhere to the pattern of white or red paint or ink  560  and wiping it from the smoother surface of the preferably glass, transparent globe  510 . The latter technique can also be used and is particularly effective with a shallow etched pattern. The etched pattern can be overpainted with white or other light colored paint  560  and then overpainted with a mask of black or other dark paint or ink  565 . 
     A stippled pattern of sprayed paint (easy and economical to accomplish by reducing air pressure as is known in the art) can thus be used as the basic pattern (different for each individual globe). With such a stippled pattern, illuminated elements are seen through the “haze” of the dark pattern overlaying a different section of the stipple. This may be better appreciated by examining FIG.  13 . 
     FIG. 13 also shows how the thickness of the illuminated circle can be made greater than the actual thickness of transparent globe  510 . Rather than black painting the interior of globe  510  or filling the globe, dark (preferably matte black) sphere  600 , somewhat smaller than the interior of globe  510  and preferably of resilient material, such as synthetic rubber (so that it can be easily installed), is suspended inside of and concentric with globe  510 . This is most easily accomplished by providing dark sphere  600  with a plurality (or even a multiplicity) of protrusions  625  sufficient to contact the interior surface of globe  510 , thereby supporting dark sphere  600 . 
     Reflections between the concave face of mirror  410  and the polished surface of globe  510  can, if intrusive, be suppressed by ordinary means or by use of perforated mirror  111  disclosed above (here being extended to essentially a full hemisphere). 
     Tracking Without A Mirror 
     Although it is preferred to install the various embodiments of illuminated globe  510  into a hemispherical mirror  410 , globe  510  (or one of the other illuminated objects discussed herein) is useful as a stand-alone tracking device. An observer, seeing that an illuminated circle is turning to follow him/her, will believe that the circle is an active tracking device. 
     In fact, particularly where a mirror is not present, useful tracking devices need not be internally illuminated. Some configurations (such as that shown in FIG.  8  and discussed below) can be brightly colored on those surfaces that would ordinarily emit light. 
     Alternate Illuminated Objects 
     A similar effect to that of globe  510  can be achieved by constructing a globe  700  of thin fins  710  as meridians. Fins  710  are oriented with their greater cross sectional dimension toward the center of globe  700 . Each fin  710  preferably has a black mask  720  along the outer periphery and the center of globe  700  is preferably filled with black sphere  730 . Black mask  720  is intended to obscure fin  710  from a reasonably wide angle. 
     Fins  710  are preferably translucent on their broad surfaces. Light can be introduced into their preferably polished upper ends essentially as for transparent globe  510  disclosed above. Or fins  710  can be solid, preferably brightly colored, and illuminated externally by ordinary means. In either case, the effect is similar to that of transparent globe  510 , but without a polished surface to cause reflections. As discussed above, the latter embodiment is useful as a stand-alone tracking device. 
     A similar embodiment can be constructed by attaching a multiplicity of brightly colored, preferably cylindrical studs to a preferably spherical black core and applying a circular black mask to the protruding end of each stud. This will produce a more uniform circle. 
     Changing the shape of the core and/or the bright elements and/or the masks can produce a variety of useful embodiments. If, for example, the core is a vertical cylinder, bright elements such as described above will appear as two parallel bright vertical lines which will maintain their separation to a viewer moving around the apparatus. Bright rings around such a cylindrical array&#39;s top and bottom will result in the viewer seeing a rectangular tracking frame. 
     Alternatively, rotating light emitter  800  may be used to create the same effect. Ring  810  (or a vertically divided half ring), is rotatably suspended from above. Shaft  820 , which supports internally transparent ring  810 , is also transparent and integral with ring  810 . The flat surfaces of ring  810  are etched to emit light and black masks  830  are applied to the curved inner and outer surfaces. 
     Preferably, the top end of transparent shaft  820  is illuminated from lamp  210  (in a lamp housing) or from a light catcher. Motor  840  drives transparent shaft  820  at preferably several hundred revolutions per minute by ordinary linkage, such as gearset  850 . Spinning ring  810  will, therefore, be visible only when generally perpendicular to the direction from which it is viewed. 
     If viewing from below is expected, it is preferable to notch the outer surface of the ring, just below the equator. Right angle notches  860  with etched horizontal surfaces and black painted (or masked) vertical surfaces will appear as rings from below. Although, depending on masking, an angled view may introduce some ambiguity in the angle and position of the added ring, the overall effect will not be disturbed. 
     It may be preferred to provide a black shell  870  over ring  810 . Black shell  870  is provided with a multiplicity of holes  875 . The depth of each hole  875  in relation to its diameter will determine (by simple geometry) how much of the illuminated surface at the bottom of the hole can be seen from a particular viewing angle. 
     Masks or light baffles, to block certain lights from certain angles, are used effectively above. Light baffles, which might be large and attract attention if used in an open space, are particularly useful in embodiments of this Invention, and in embodiments of the Patents incorporated herein. In most embodiments of all of these inventions, dark objects behind the mirrors are invisible. In some cases it may be preferred to vignette the edges of baffles to soften the transition as a light appears from or disappears behind a baffle. 
     Baffles are used in a sometimes-preferred alternate to the globes disclosed above. Although this alternative may be illuminated in various ways, illumination from the top, from a lamp housing or light catcher by light conduction as disclosed above, is preferred. 
     An illuminated, flat red circle  251 , as preferred in the first preferred embodiment, is positioned about the center of curvature C of hemispherical mirror  410 . A cross-shaped aperture is preferably cut through the center of the face of lamp housing  201  with red circle  251 . Mounted into the face of lamp housing  201  is a light transmissive (such as acrylic) structure  15  in the shape of two planar members crossing at 90 degrees at the center of the circle. If this structure is actually made of two planar members (such as acrylic sheet), the joint(s) should be masked in black. Each of the four segments of transmissive structure  15  has, etched into each face of its inner corner (the one in contact with the center of the red circle), a 90-degree segment of a circle. Red circle  251  and each of the circle segments are of equal radius, preferably about one tenth to one fifth of the mirror diameter. The planes of transmissive structure  15  are preferably red, to match red circle  251  (or can be illuminated with red light). The balance of the surfaces of transmissive structure  15  are painted opaque black. These protruding surfaces are baffles to interfere with the view of parts of the illuminated circle segments from various angles. 
     In use, the viewer sees a red image which is, for most points of view, not a circle. The red image may, from many points of view, be interrupted in spots by parts of the baffling planar members. Nonetheless, the image is fairly economical to produce and, although its shape is somewhat plastic, it will not close up like an ellipse and will look reasonably the same from any point of view. 
     In some embodiments, it may be preferable to use a circular neon lamp or a pattern of light emitting diodes (LED&#39;s) as the red circle. 
     Bells &amp; Whistles 
     The effect of the tracking mirror can be enhanced by modifying or adding elements to 
     Other two and three-dimensional shapes may be used as stand-ins for the red circle. 
     Fiber optics and light the preferred embodiment. 
     For example, in the first preferred embodiment  100 , disk  350 , which defines the center of red circle  250 , can be mounted to a (preferably about 30 rpm) motor  841 . Tab  351 , added to the edge of disk  350 , makes a gap in circle  250 , which revolves to suggest a radarlike device. 
     With a larger revolving disk  355 , having several apertures near the edge, the circle is replaced by a rotating ring of lights. Particularly if the disk is contoured, ambiguity of the light&#39;s actual position in space is enhanced, in some cases sufficiently for use in a hemispherical mirror  410 .conductive rods, holograms and lenticular screens can be used to advantage. 
     A particularly effective enhancement is to add a pair of screens  910  in front of red circle  250  (preferably close to red circle  250 , where they can be smaller). Screens  910 , which may be perforation patterns or printed on transparencies, create a moire effect, causing much activity in red circle  250  as the viewer changes location. 
     The circle itself and/or the globe of the second preferred embodiment can also be patterned to form part of the moire assembly. 
     While the Invention has been described with reference to preferred embodiments thereof, it will be appreciated by those of ordinary skill in the art that modifications can be made to the Invention and to its uses without departing from the spirit and scope thereof.