What they call 4 rivers was on the atari st as Matchit back in about 1990 I think. I always loved the game so in 2001 I wrote a blitz version. It's based on Matchit so that the number of tiles increases each screen and you've got a timer but the tiles are still removed in the same way. I don't have a web page but if you'd like to try it I'd be happy to email you a copy of it.