In the United States, approximately 5000-6000 toy industry products are introduced each year, most of which are created by research and development specialists at the more than 800 toy manufacturers based in the United States.  Toy industry retail sales in 1996 rose to an estimated $20.7 billion, up from $20 billion in 1995.  Manufacturers shipments totaled $13.94 billion in 1996 versus $13.45 billion in 1995.  Of the major product categories, the strongest performers were dolls, up 12 percent, ride-ons up 10.4 percent and games/puzzles, which registered a 7.5 percent increase.  Annual retail sales estimates are based upon a constant gross profit of about 33 percent and do not include video hardware and software sales. 
Many of the toys which garner the most attention reflect the latest technological advances or are innovative extensions of basic products.  Along with providing opportunities for fun and learning, toys traditionally mirror scientific progress, changes in social attitudes and topical customs and values from the adult world. 
At the earliest stages, many toy designers utilize information from sources including parents, psychologists, educators and other child development specialists.  This background provides valuable clues as to what consumers are looking for when they purchase toys.  Toys also are frequently tested by the children themselves in focus groups or at home to determine durability, age appropriateness, play patterns and marketability.  A number of toy manufacturers maintain in-house, year round nursery school facilities for this purpose, while others establish relationships with universities and other research facilities. 
Many factors influence the success of a given toy or product line, including perceived value, multiple play possibilities, eye catching design, innovative line extensions, creative marketing, proper in-store exposure, reasonable availability, and positive "word of mouth", i.e., child-to-child, parent-to-parent.  However, one characteristic that is present in most of the toys that prove to be best sellers, is interactivity.  Interactivity is basically the toys' ability to respond and provide a response to input or action by the user.  While less mature or younger children are content to play with inert toys such as blocks and teddy bears, more developed children are searching for something more, in the form of a toy which can provide some response to their actions. 
While the majority of adults outgrow the use and enjoyment of toys after their teenage years, they still seek out devices and products which can provide stimulating and gratifying enjoyment.  This sector of the marketplace is often occupied by sport related or therapeutical products.  For example, a myriad of exercise machines exist today, ranging all the way from a simple grip strengthener all the way to complex ten-station workout machines.  Again, while the more inert products such as a simple punching bag are popular, the devices which can provide the user with instantaneous and instant feedback are the most popular.  Recent trends for modern products incorporate the use of devices such as performance monitors and vital sign readouts for heart rate, blood pressure, etc.  Thereby, it would be desirable to have a product which can provide both children and adults with instant gratification in the form of a responsive toy or recreational device.  It would be further desirable if this product could be implemented in a variety of existing devices to make them more interactive in nature.