Stack

Stack is a free online tower-building game you can play instantly in the browser. A block slides back and forth above the tower — drop it at the right moment to land it square, and build as high as you can. Simple one-tap play, no download and no sign-up, on phone or desktop.

How to play

• A block slides left and right above the top of your tower.
• Tap, click, or press space to drop it onto the block below.
• Any part that overhangs the block beneath is sliced off and falls away.
• The next block is only as wide as the piece you just landed.
• Each successful drop adds one to your score and raises the tower.
• The run ends when a drop misses the tower completely.

Aim for a near-perfect overlap: a drop that lines up almost exactly loses no width, so the block stays wide and the game stays forgiving. Once a block narrows, slow down and focus on timing over speed — a thin tower punishes even small errors. Watch the block's edge rather than its centre, and release just before it reaches the same edge as the block below.