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3 D Vinci: Free Stuff for Everyone
Free projects and video tutorials on using Google SketchUp to make 3-D models. For K-12 and also for adults. A teaching guide is also available.
Math Is Fun
Math Is Fun: Making 3 D Solids
This tutorial features templates and instructions to make the following solids: tetrahedron, cube, octahedron, dodecahedron, and icosahedron.