This article is one in a series of Instructables articles about DIY technology. The full list can be seen here.
Step 1: Sand Castles
Imagine you have a tray and coat the bottom with a fine layer of sand. You then took some glue and drew a circle in the middle, creating a ring of glued sand. Now take some more sand, spread it evenly on top, and draw another circle with the glue, gluing a new ring of sand to the previous one. Keep repeating this process off adding a layer of sand and gluing circles and eventually there will be a glued sand cylinder inside the tray of sand.
Now, if you reach in to the tray of sand, you can pull out a hollow cylinder of sand. By choosing the radius of the circle and the number of layers you can get the exact dimensions that you want. If you made each circle a little bit smaller you would get a cone. Get creative and you can make any shape you want.