About this game

There is one little wooden stool with a green felt top, and one tower that both players build on it. The pieces are made of modelling clay: planks, blocks, bricks, triangles, wedges, a pebble, a blob, an L, a zigzag and an arch. Both players take them from the same pile, and the next piece is always shown in the corner.

On your turn the piece hangs above the tower. Drag it left or right, and turn it with the arrow buttons or by twisting two fingers. A dashed outline shows where it will land. Then press Drop. The piece falls, the tower wobbles, and once everything has stopped moving it's the other player's turn.

If anything ends up off the stool during your turn, even a piece someone else put there, you lose. If all 40 pieces stay up, the game is a draw.

On your own, you play against the computer. It tries dozens of drops in its head before it lets go. Easy picks one of its better tries and sometimes wobbles its aim, so children can beat it. Hard picks the steadiest spot it found. Players take turns to go first.

Good for

• Two children sharing one phone or tablet
• Talking about balance: where is the middle of the tower, and why did it tip?
• Wet play, or a quick game for two finishers at the end of a lesson