Daniel-san wrote:Doors turn on hinges. Is a hinge a wheel?
They're both applications of "the lever". The hinge is synonymous with fulcrum and a wheels axle.
Or is the hinge just a part of the door, like the knob? Do we need to consider the most complex example or the most fundamental.
A door may make use of a hinge and lever but I submit a door need not be movable to be functional.
Leaving aside the entire multiverse of conceptual doors and gates