LITSO (579)

Instruction:

Divide the grid into tetrominos so that two identical tetrominos never share an edge (but may touch diagonally). Tetrominos that are rotations/reflections of each other are considered identical.

Reference: WPF (1)

Examples:

WPF Puzzle GP 2014 - Round 2 (88)

WPF Puzzle GP 2014 - Round 5 (91)

Parent puzzle:
Tetrominous

Child puzzles:
Tetrominoes End View