Tileset
A tileset is a set of graphical tiles used in roguelikes to substitute the regular ASCII graphics, creating a GUI. It works by defining a set graphical tile for every symbol and object in the game. Graphical tilesets are often beneficial to new roguelike players who are not accustomed to the usual graphics-free style roguelikes are presented in.
Since Crawl 0.4, tiles have been integrated into the official releases: select "tiles version" or the unified installer.