This is a call for help—or for suggestions, at least. I’m teaching a knot theory class next semester. I’m looking for good props to use in the class to make knots. I would like to be able to make knots such as the following (and have my students do so as well). I suppose the criteria are:
- Inexpensive (It would be nice to find something that is cheap enough that I can ask the students to buy it without forking over too much more money on top of what they are paying for the text.)
- Holds its shape if set on the table
- Long enough to make complicated knots
- Short enough that it is possible to see what is going on
- Easy to disconnect, knot/unknot, and reconnect (I’m thinking of velcro ends, snaps, plugs, something like that.)
This is what I have come up with so far. 1. Rope/string—satisfies a lot of the criteria, except #6. If anyone can think of a good way to attach a connector to the ends of a piece of rope, let me know. 2. Extension cord—this is a pretty good solution if I can find one of the right length and flexibility. 3. Tangles—a fun toy made out of many snapped-together pieces of quarter-circle-shaped tubes (see below). It is easy to plug and unplug the links of the toy. Fun to play with, but the knots are very “wiggly” looking and we would need several sets to make a long knot.
4. Rubber tubing—I bought some 1/4″ vinyl rubber tubing and some connectors (shown below). This works pretty well. The tubing plugs and unplugs easily. The downside is that the tubing doesn’t hold its shape well. It has a memory and wants to straighten out on its own.
5. Smart Bungees—I had never seen this product before. They are bungee cords without hooks on the end. Instead it has plugs that you can snap into any number of different adapters (sold separately). I bought a set of two bungees (48″ each) for about $5 and a pack of two connectors (as shown below) for $2. I won’t ask the students to buy this, but I think I may use this for demos in front of the class.
Ideas?!?! Let me know. Thanks!