A tetris-like game for MacOS. I'm afraid don't remember who wrote it. You get pairs of colored globs. They fall down as far as they can go, possibly seperating from eachother. If two globs of the same color are next to eachother they will join to become one larger glob. If a glob contains 4 or more of the original globs it disappears and everything on top of it falls down. It is possible for other globs to fall apart this way.

You play against an opponent, or a bot. If you cause globs to disappear your opponent gets rocks dropped into his shaft, making it more difficult to complete globs. If a glob disappears next to a rock the rock disappears as well. The more globs you get rid of in one go, the more rocks your opponent receives. It is possible to play at different difficulty levels, with different numers of colors.

There is a GPL version of this game, called xpuypuyo, written by Justin David Smith, Owen Aftreth, Denny Mingus, Brett Smith, Andrew Carpenter, Havoc Pennington and theGREENzebra. It is basically the same, but the MacOS version has some really funny sound effects that xpuyopuyo doesn't have.