The Square-1 is a puzzle shaped as a cube. This puzzle was created by Karel Hrsel and Vojtech Kopsky in 1990. The original name for this was "Back to Square 1" but was later shortened to "Square 1".
The Square-1 has three layers: the upper and lower layers- which consist of triangle(corner) and kite(edge) pieces- and the middle layer which has two trapezoid pieces. It can shapeshift.