Ordinarily, one perceives discrete objects set off from distinct grounds. There are situations where the distinction between what is figure and what is ground oscillates, as does the Rubin vase-and-faces pattern. There are even situations where a figure's ground is a part of itself, where discrete figural features slip out of a ground and back into it. These visual curiosities can be induced by figure-generating contours, which are created by a field of color or texture that is self-interrupted and that conforms to the topology of the labyrinth.