[EricH]

Simple... or, as Woodie so elegantly put it in 2007, "Simplicity on the other side of complexity"?

I think the question could be phrased this way: What is the minimum X device to do Y function effectively, given that Z group can't do anything beyond A complexity? If you go below the minimum X, you fail--Y isn't effective. If you go beyond A, you fail--Z can't do it without risking pain in terms of time, weight, or cost. If you are at the minimum X and at A, you have a simple, and quite possibly elegant, machine. (Going beyond X can result in greater complexity or greater capability, depending on the manner. For example, scissors lift versus linear elevator versus single-joint arm versus multi-joint arm in the 2007 game.)