一樣是在 Boing Boing 看到的：Lego logic，原 link 在 LEGO Logic Gates… 用樂高積木… -_-
I have now designed working NOT, OR, NOR, AND, and NAND gates. Using two NAND gates I have produced a NAND gate latch or Flip-FLop. The natural follow on from these is clocked logic, full-adders and ultimately a genuine “computer” device. At the moment all these gates essentially just demonstrators. They work, but because of the limitations that arise through gear slippage, the real practicable use is probably not that great.