1. One empty tin can. The type of cans with ringpull lids are best, because they don't have any sharp edges. (And make sure you wash the can out before using it!)
2. A wooden ruler at least 30cm long.
3. An empty matchbox, with the inside drawer removed.
4. Two paper-clips and two spent matches.
5. A small piece of plasticine or modelling clay.
6. Some strong thread.
7. A piece of wood.
8. A hammer and a small nail.
9. Some sticky tape and some paper glue.