I was fascinated by a "puzzle version" of this problem as a child, and a couple of years ago I wrote some little Processing applets to explore the idea of "gami

I was fascinated by a "puzzle version" of this problem as a child, and a couple of years ago I wrote some little Processing applets to explore the idea of "gamifying" it: https://cjauvin.blogspot.com/2012/02/implicit-bridges.html https://cjauvin.blogspot.com/2012/02/implicit-bridges.html https://cjauvin.blogspot.com/2012/02/eulerian-hoax.html https://cjauvin.blogspot.com/2012/02/eulerian-hoax.html