We have indeed looked into that. As far as I could distill, the problem is on the worldwide trademark Tetris©®(tm) that some people use to designate the type o

We have indeed looked into that. As far as I could distill, the problem is on the worldwide trademark Tetris©®(tm) that some people use to designate the type of game. The word to use is Tetrominos, then the game itself does not need licensing.