StrandBeest Compleat
Strandbeests are movable sculptures by Theo Jansen - find out more from
http://www.strandbeest.com/ or http://www.ted.com/talks/theo_jansen_creates_new_creatures
It's quite fun to play with the constants to change the leg. Small changes can make huge differences. Even though Theo's isn't, I wanted C, D', F, E to be a rhombus, but finally added te nudge for F because it really changes the walk.
Here's a beest by the inventor of GeoGebra, Markus Hohenwarter: https://www.geogebra.org/material/show/id/17499
Hope you have some fun playing!
If you download a sketch there's a tool for building legs, but it's pretty finicky. Points are like A, B' (rotating) and C, numbers a, b, c, nudge and time parameter, t.