[Peter Lehnér] has designed a brilliant 7-segment flip-segment display that doesn’t really flip. In fact, it doesn’t use electromagnets at all. This one is 3D printed and hand cranked. … ...

He started with a bag full of NE-2 tubes and the realization that a 3D-printed frame would let him create his own seven-segment displays. ... .0 of the calculator regressed to all-relay logic, ...