The Dutch DAF 55 variomatic, introduced in it was the beginning of CVT automobile transmissions. Two transmissions were used to accommodate differential wheel speed during turning and it gave the effect of limited slip drive.
The hanging Spirals staircase. This design makes sweeping under the stairs easy! A hanging double spiral staircase is part of the Didden Village project in Rotterdam. There are two such staircases; the other is a single spiral.