pub fn four_bar_assembly() -> ProgramExpand description
The assembly of four_bar: a four-bar linkage of bars — the ground
(4 long, fixed), the crank (1.5) and the rocker (3) each pinned to one end
of it and lying on it, and the coupler (4) pinned to their far ends,
lying on the crank. The crank is the shortest bar and
1.5 + 4 ≤ 4 + 3, so it turns all the way round while the rocker rocks.