The eight tile problem?

Wang's algorithm for determining whether a given set of tiles can tile the plane was not correct. In fact, no such algorithm can exist. It is possible to translate any Turing machine into a set of Wang tiles, such that the Wang tiles can tile the plane if and only if the Turing machine will never halt. The halting problem is undecidable, therefore the Wang tiling problem is also uncomputable. In a sense, Wang tiles have computational power equivalent to that of a Turing machine.