Further Feet

Following on from my last foot-finding foray, I've done some more experiments. It's possible to cut a tennis ball in half in a zigzag sort of way, so that the halves each fit neatly on a cube corner. There are four downsides of using tennis balls, though:

• They're really difficult to cut in half;
• The hair falls off them (especially along the cut) and gets everywhere;
• They have a second-hand value, so they're cheap rather than free;
• They're quite bulky.

So I'm not convinced that tennis balls are a good solution.

I also tried cutting bicycle tyre into pieces that fit better on a corner. The previous design for this used three separate strips for each corner; unless constructed very cleverly, it's likely to open up along the diagonal and not protect the corner as well as it could. This new design uses only one piece but stays over the corner better.

The prototype is similar in shape to the sort of sticking plaster that is designed to go on an elbow – for similar reasons. The only downside of it is that it doesn't have the same rotational symmetry that the earlier tyre-based design had. However, I think a final design could be more equilateral in shape.

It would be useful to work out a way to use a template to cut the pieces of tyre accurately and quickly. I doubt that jig saws work on rubber.