Three different designs of tile sets are included with Mombasa, and you can also design your own (see "Creating a Tile Set"). The 3 included are Afrika, Mental Blocks, and GeoTiles. The major consideration in which tile set you prefer will probably be aesthetic, but some sets are easier to spot matches in than others. GeoTiles in particular is recommended only for masochists.
To choose a new tile set, just pull down the Tile menu. All the tile sets will be listed, including any you have added. Pull down to your new choice.
Warning: Changing tile sets causes the current game to be abandoned, and a new game to be started.
