Shadow Stack
Shadow Stack turns two flat silhouettes into a compact construction puzzle. Set the height of each occupied cell so every row maximum, column maximum and the total block count agree at once.
Play Shadow Stack
Free in your browser. No download required; open the game and start a fresh challenge.
How to play
- Use the footprint to see which cells must contain blocks.
- Set each occupied cell height while matching the row and column silhouette maxima.
- Check the sculpture when the total block count and both projections agree.
What to expect
- Every generated board retains a verified solution and is rechecked by an independent constraint solver before play.
- Multiple valid sculptures are accepted; the game never requires guessing the generator’s original arrangement.
- Practice uses three boards and up to three checks per board, with no speed bonus.
Difficulty
Easy uses 2×2 boards, Medium uses 3×3 and Hard uses compact 4×4 boards with higher stacks.
Frequently asked questions
Is Shadow Stack free to play?
Yes. Shadow Stack is free in your browser with no download and no sign-up required.
What should I know before playing Shadow Stack?
Every generated board retains a verified solution and is rechecked by an independent constraint solver before play.
How does difficulty change Shadow Stack?
Easy uses 2×2 boards, Medium uses 3×3 and Hard uses compact 4×4 boards with higher stacks.
Do I need an account to keep my scores?
No. Daily scores and lab games work as a guest. Creating a free account keeps your profile, streaks and Rival history across devices.