Foucault's pendulum is moving to and fro along the same course. It seems however that it rotates slowly. This illusion is caused by the rotation of the Earth placed underneath it.

In the middle of the room there is a brass weight (plumb-line) hanging on a golden string. Underneath it - mounted in the floor - mirror.

Skirting-boards are removed from its "normal" positions and, painted gold, are situated on the walls according to the directions pointed by compasses set in the centre of each wall.

The line created by the skirting-boards due to the door opening continues in the first room joining the door-wings into its course  - one of the wings is upside-down.