See Wikipedia article "Wang Tile" for more information and the source of the images used here. Drag the tiles shown. You'll often see that because a new row or column would have been impossible to "fit" next to an existing edge, the solver had to backtrack and modify the edge tiles so that the new edge would fit. Sometimes it is forced a couple edges back towards the tiling's center.

Solving to more than about a 7x7 tiling grid is too slow to consistently scroll in real time with this algorithm. Additionally, because only a small grid is stored in memory at any one time, repetition occurs. I.e., a "strip" of Wang tiles can have repeating sequences of specific columns or rows. Because this solver favors solutions which require the fewest modifications to already-placed tiles as new tiles are placed, a given row tends to favor another specific row (out of other possible arrangements, which would have required more backtracking), and loops easily occur.