Tetromino
A tetromino, sometimes called tetramino or tetrimino, are four-squared polyominoes. The seven tetrominoes are i, o, t, s, z, j, and l.
i
Other names include straight, stick, and long.
o
Other names include square and block.
t
s
Other names include inverse skew.
z
Other names include skew.
j
Other names include gamma or inverse l.
l