Non-Digital Computers This is the last installment of my many-part series on computers. Last time we used the notion of a Turing machine to define what a computer is. We discovered something surprising: that not all computers need to be digital, or even electronic! A computer can be mechanical,  made of dominoes, or even just a rules system in a card game. To give you of a flavor of how inclusive the definition of a computer really is, I’ll now give you a whirlwind tour of some notable examples of non-digital computers. The Antikythera Mechanism In April of 1900,