according to physics levers are of 3 different types:

F: Fulcum
L: Load
E: Effort

Class 1: L - F - E (scissors)
Class 2: F - L - E (wheelbarrow)
Class 3: F - E - L (biceps)

what type of lever is the best type of lever? is it possible to build a lever that doesn't fit any of those 3 types?