I came for the collapse and stayed for the backtracking.

It is trying to make ends meet. Will the loose end make it?

This ones comes with wrap-around and varying tile probabilities.

I tried to make the backtracking a bit more clever - now it attempts to push the bubble-that-doesn't-fit towards the edge of the carpet.

Added over-and-under bridges and color probabilities.

This one comes with a "discriminator" that hates little squares and erases them whenever it finds them, so the tiler has to go back to the drawing board and find a better solution.