Lehmer sieve

A Lehmer sieve will signal that such solutions are found in a variety of ways depending on the particular construction.

[1] Built in 1932, a device using gears was shown at the Century of Progress Exposition in Chicago.

When the holes lined up, a light at one end of the device shone on a photocell at the other, which could stop the machine allowing for the observation of a solution.

Brushes against the rollers would make electrical contact when the hole reached the top.

Again, a full sequence of holes created a complete circuit, indicating a solution.

A Lehmer sieve - a primitive digital computer once used for finding primes and solving simple Diophantine equations .