Tetro Shade Solver

Tetro Shade Solver — Step by Step

Drag across squares to join them into regions, then press Solve. Or play a generated puzzle and send it here with one click.

Tetro Shade Solver: rules, how to use it, tips

Shade one piece of four connected squares (an L, I, T or S) in every region so that everything joins up, with no 2×2 blocks and no matching shapes touching.

The rules

Every region contains exactly four shaded squares, joined side to side — a tetromino.
All shaded squares in the grid form a single connected group.
No 2×2 block of squares is completely shaded.
Two pieces of the same shape (counting rotations and reflections) may not touch along a side.

Using the solver

Choose the size and draw the regions (or press Sample).
Press Solve and step through: ways a piece can fit, 2×2 blocks, matching shapes and connections.

Tips

Four-square regions. A region of exactly four squares is its own piece — shade it all.
Common squares. List the ways a piece can fit; a square used by every way is shaded.
2×2 watch. Three shaded squares in a 2×2 block make the fourth white.
Stay connected. A square whose whiteness would cut the shaded group in two must be shaded.

The full guide, with a worked example and common mistakes: How to play Tetro Shade.

Questions

Are mirror images the same shape?

Yes — an L and a backwards L count as the same, and so do the two S shapes.

Can two different shapes touch?

Yes — only matching shapes may not share a side across a border.

Is there always one answer?

Yes — every puzzle here is checked to have exactly one solution.

How do I solve one from a book?

Open the Tetro Shade Solver, draw the regions and press Solve.