When you buy through links on our articles, Future and its syndication partners may earn a commission. Credit: Anson Smart. Design: Studio Doherty No longer just a way to get from A to B, stairs are ...

Wandel’s slinky machine was carefully tested to be the right size and speed for a slinky toy, allowing the slinky to drop from stair to stair indefinitely. The building and testing process looks like ...