low-speed special-purpose digital computer built of TinkerToys / who needs electricity to compute? MIT doesn't!

Click, good things might happen.

Laugh all you want, but actually there's Big Buck$$$ in developing digital computation systems that don't use electricity or electronics. The Big Bucks, of course, come from the military, which is always wondering how they'll be able to keep on computing after a thermonuclear war. H-bombs exploding in your neighborhood generate a thing called EMP (electromagnetic pulse) or Big Pulse, which wipes out the ability of electronic and electrical circuits to function.

But this TinkerToy computer wouldn't even notice the effects of Big Pulse, and would merrily keep on playing a very competitive game of Tic-Tac-Toe as if nothing had happened.

This low-speed special-purpose digital computer was invented by Massachusetts Institute of Technology students, and is now on public display at Boston's Museum of Science.

MIDDLE: A schematic diagram of the TinkerToy tic-tac-toe computer, from A.K. Dewdney's "Scientific American" Computer Recreations column.

BOTTOM: Just because I couldn't resist, the world's first computer game, from 1952, tic-tac-toe on EDSAC, an Ur-computer from Cambridge University in the UK. EDSAC came alive in 1949 and appears to be the first electronic digital computer that could be programmed in software (i.e., without having to plug and unplug wires and physical elements).

Filched from RetroThing:

This brilliant Tinkertoy digital computer was built by a team of students at MIT in the 1980s. It's a marvel of mechanical design that apparently plays a "mean game of tic-tac-toe." The idea was born in 1975, when two sophomores worked on a class project to build something digital from Tinkertoys. It took another few years before they collaborated over the phone to design a working machine for the Mid-America Science Museum:

"A Tinkertoy framework called the read head clicks and clacks its way down the front of the monolith. At some point the clicking mysteriously stops; a "core piece" within the framework spins and then with a satisfying 'kathunk' indirectly kicks an 'output duck,' a bird-shaped construction. The output duck swings down from its perch so that its beak points at a number [from 1 to 9] -- which identifies the computer's next move in a game of tic-tac-toe."

The Tinkertoy Computer is now on display at the Museum of Science in Boston, where it will undoubtedly inspire legions of future Tinkertoy scientists. Here's a link to a behind-the-scenes article from the October 1989 issue of Scientific American.