For example, the Vectrex games and the GCE handhelds*. With much gratitude to baronvr, here is a RealAudio recording of a speech that Tom made at the 1999 Classic Gaming Expo in Las Vegas, about how the design for the (now) classic Vectrex game SPIKE came about.
* Want to see the GCE game watches and game calculators, and read about how they were designed? Click here!