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Step 6: Prepare the Molds

Before you start mixing your concrete, you need to prepare a support for the molds. Because the icosahedron has a pointed tip, it won't stand on its own. I used a jar and a roll of tape as support, but anything with a similar opening will work.

Fill the inner mold with sand or small stones. This is necessary because otherwise, the mold would just float on top of the concrete.