Anti-Letter Tetromino

Rules

Divide the grid into tetrominoes. The shape of each tetromino must be different from shapes represented by letters inside the tetromino. No same letters cannot be placed inside the same tetromino.

(Example from WPC 2015 IB)

History of the puzzle

Invented by Kazunori Saitoh (Japan). First appeared on WPC 2015/Round 10.

Appearances in the past WPCs

• WPC 2015/Round 10 by Kazunori Saitoh