Squaretris

Colour palettes from Sanzo Wada's Dictionary of Colour Combinations (1933)

Top/bottom pieces: ← → to shift  ·  ↓ ↑ to accelerate
Left/right pieces: ↑ ↓ to shift  ·  → ← to accelerate
Z = rotate  ·  Space = hard drop  ·  C = clear largest square
Build any N×N filled square anywhere — then clear it for big points!
Don't let a piece bypass the pile or it's game over.