Today's low-power electronic devices can throw off a lot of heat, and engineers must find ways to dissipate it.
In 1946, Dick Tracy strapped on a two-way wrist radio and modernized crime fighting in the comic pages of America. Some 20 years later, in 1964, Chester Gould's fictional detective upgraded to a two-way wrist TV. Then, in 1986, Tracy began wearing a two-way wrist computer.