Pentomino Games

My friends keep telling me there is a 5-square blocks in the Tetris game Tetris, and I disagree. In all the games I played Tetris, I never ever seen a pentominos. AT. ALL. One went so far as to say that there is even an online 6-piece square. Their claims really angry nerd inside of me because why the hell would it be called Tetris (and I am sure that the prefix tetra is Latin for 4 ...) if there were 5-or 6-square- Tetris blocks in the gameplay? Please help!

As far as I know, the original game, which came from Russia, called tetris for the reason you play a puzzle game with 4 blocks falling from above, and you need to fill a line with these blocks to keep them away to reach the top

if a game like Tetris that was a quarter of a block as a supplement, I would say that someone mad a fan made game

btw, just for the record, there is a Tetris like game with three columns called blocks, for the Sega Genesis