LITS rules

LITS is a puzzle type originally created by Nikoli.

Place exactly one tetronimo into each outlined region. All tetronimos must form a single connected group. You can not have a 2×2 square of shaded cells, and two tetronimos of the same shape can not be orthogonally adjacent.

See this example puzzle and its only solution.

The four usable tetrominos are below.

LITS example