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The Think-a-Dot was a mathematical toy invented by Joseph Weisbecker and manufactured by E.S.R., Inc. during the 1960s that demonstrated
Picture of a Think-a-Dot
3-D printable Think-a-Dot Replica
Mechanical puzzles
The Think-a-Dot was a mathematical toy invented by Joseph Weisbecker and manufactured by E.S.R., Inc. during the 1960s that demonstrated automata theory
Automata theory is the study of abstract machines and automata, as well as the computational problems that can be solved using them. It is a theory in theoretical computer science. The word ''automata'' comes from the Greek word αὐτόματο� ...
. It had eight coloured disks on its front, and three holes on its top – left, right, and center – through which a ball bearing could be dropped. Each disk would display either a yellow or blue face, depending on whether the mechanism behind it was tipped to the right or the left. The Think-a-Dot thus had 28=256 internal states. When the ball fell to the bottom it would exit either to a hole on the left or the right of the device.
As the ball passed through the Think-a-Dot, it would flip the disk mechanisms that it passed, and they in turn would determine whether the ball would be deflected to the left or to the right. Various puzzles and games were possible with the Think-a-Dot, such as flipping the colours of all cells in the minimum number of moves, or reaching a given state from a monochrome state or vice versa.
See also
* Digi-Comp I *Digi-Comp II
The Digi-Comp II was a toy computer invented by John "Jack" Thomas Godfrey (1924–2009) in 1965 and manufactured by E.S.R., Inc. in the late 1960s that used marbles rolling down a ramp to perform basic calculations. A two-level masonite platfo ...
* Dr. NIM
Dr. Nim is a toy invented by John Thomas Godfrey and manufactured by E.S.R., Inc. in the mid-1960s. It consists of a marble-powered plastic computer capable of playing the game of Nim. The machine selects its moves through the action of the marbl ...
References
*. *. *{{citation , last = Gemignani , first = Michael , doi = 10.2307/2689850 , issue = 2 , journal = Mathematics Magazine , mr = 1572295 , pages = 110–112 , title = Think-a-Dot: a useful generalization , volume = 52 , year = 1979.External links
Picture of a Think-a-Dot
3-D printable Think-a-Dot Replica
Mechanical puzzles