The rotary mast (4) describes a vertical circle. The passenger gondola (5) on one side of the rotary mast moves at the same speed in the opposite direction on an axis lying on the same circle.The axis lies at one end of the rotary mast and in the middle of the gondola which also describes a vertical circular movement on the same axis. The superposition of the circular movements causes the ends of the gondola to describe a trajectory nearly equalling a spherical lune.
