Most Tetris clones with character graphics used two characters for a block (just like the original Tetris), Tore Bastiansen used one character in 40-column mode for his Small Tetris; Hector Noriega's TetraFix has the largest blocks, made out of eight characters each. His pieces are all the same color, but change it when they reach the bottom. The background pattern is randomly chosen at the start of each game. Many of these patterns are rather elaborate, and TetraFix is one text mode game that definitely does not look better on CGA.
Basically, gameplay is pretty much the same as the original Tetris, except that you get the extra surprise of a bomb now and then. But the well is rather short (12 rows instead of the usual 20), calling for a different strategy. Trying to get a Tetris (four rows cleared at once) will nearly always result in a disaster.
TetraFix is a single executable with 11kB.
For unknown reason TetraFix is sometimes listed as an adult
game. Don't believe it, it is not. There are a few adult
Tetris
clones, most notably Porntris,
XTET, and, yes, Bubble Bath Babes. TetraFix is not among them.