Build it then knock it down

Pile up whatever stacks well on the floor — blocks, plastic cups, books, anything.

Stack 3–4 items. Knock them over with a deliberate gentle push.

Pure joy at the knock-down. Then rebuild — the build is the price the child pays for the knock-down. The schema is the cycle, not the result.

Stack high. Stack in a row to topple like dominoes. Build with one hand. "How tall before it falls on its own?"