Here is a quick flow.
Do not know if it is the same in the physical world.

1. Construct a circle of diameter 10
2. Construct a line of length 10*PI =~ 31.41592653589 (by typing in the value in the___ box.)
3. Create a helix of say 10 turns, radius say 2, using the line as a length snap.
4. Run flow by selecting 1. helix, 2. line, 3. circle.

Edit, whoops I think I made a toroid. Need to constrain the coil a rectangle...???
Ignore this post.