Helix

File:VaticanMuseumStaircase.jpg
The staircase in the Vatican Museums. This shows a helix.
File:DirkvdM natural spiral.jpg
Spiral of a climber plant, also a helix

In math, a helix is a curve in three dimensions. It looks a bit like a spiral. Each helix has a line called its axis. The helix has a constant angle to this line. Helices are often seen in nature and the sciences.