8. To make the feet, cut out two 75 mm diameter circles from some 2 mm thick plastic sheet - the flat tops of aerosol can lids work pretty well too. Glue the feet to the hoops on the ends of the legs using hot glue or Araldite.

9. Slide the top end of the leg into the 3 mm hole in the leg mounting so that it sticks out at one side by about 20 mm. The leg is then fixed in position by the M6 grub screw, which tightens onto the flat at the top of the leg to secure it. Then bend the legs using pliers and/or self-securing grips, so they are at the right angle for running. This can take a bit of trial and error. (Getting the centre line of each foot to be about 80 mm from the centre line of the lizard, and the foot to be flat and level when about 6 mm below the level of the base of the lizard's body seems to work quite well. When level, the centre of each foot is about 60 mm in front of the shaft it is attached to.)

10. Attach the rubber bands by hooking one end between the head of the bolt and the aluminium rod on the drive shaft, and the other at the back of the lizard, underneath a nut at the bottom of the M8 studding. Hook the other band over the nut on the other end of that M6 bolt and then stretch it over the hook over the M8 studding at the other end. This one fixes to the top of the M8 studding and is held there with an M8 nut near the top. The lizard is primed for running by rotating its feet backwards, twisting the rubber bands up until they feel pretty tight – too tight is not necessarily better.

11. Get the lizard to run on water by holding it at water level and letting go of the legs. It should sprint off for at least a few metres.

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Content last updated: 02/09/2005