Nine easy pieces—shapes made of 2, 3, 4 and 5 equilateral triangles joined—fill the encircled pattern and form a large variety of shapes outside the ring, too. For the toughest challenge, have no two of the same color share sides.

How to play

Move the pieces by dragging them.

Rotate the pieces by clicking them.

Flip the selected pieces by double-clicking them.

Challenges: presented with the numbers 1, 2, and 3 respectively.