Conway packaging problem

The box containing the eight pieces seems to fit them just right,
So how is it possible that a ninth part can also fit into the box?
Surprisingly, this is possible.

Try to fit all nine pieces into the box.
Of course, with the ability to close the box with all nine pieces at the end of the game.

Packaging: Shrink

Level: 4

Weight: 349 g

Wadel: 65 * 115 * 45 mm

Do we need the solution?