“A useless box is a device which has a function but no direct purpose. It may be intended to make a philosophical point, as an amusing engineering “hack”, or as an intellectual joke. Devices which have no function or which malfunction are not considered to be “useless box”.
The most well-known “useless box” are those inspired by Marvin Minsky’s design, in which the device’s sole function is to switch itself off by operating its own “off” switch. More elaborate devices and novelty toys, having some obvious function or entertainment value, have been based on these simple “useless box”.
Source https://en.wikipedia.org/wiki/Useless_machine
Today I am going to share how to make one”