Step 1: Gather your materials.
Step 2: Making the Rotor.
Cut three pieces of foil. The exact dimensions for the basic motor are not important, but they need to be slightly shorter than the cup is tall, and of a width so that there is a gap of about 1cm between the pieces when you stick them to the cup.
Stick the pieces of foil to the cup. Space them evenly around the cup, and make sure there is no point where neighbouring pieces touch each other.
(I say "three pieces of foil", but the exact number seems unimportant - maybe somebody would like to research this point - as long as it is two or more.)
Step 3: Making the Base and Adding the Rotor.
It is possible to sharpen the dowel with a pencil sharpener, or even use a sharp pencil instead of the dowel. Bamboo usually needs a sharp knife.