Symmetry, groups and who knows what else? - A dynamic book motivated by questions

Avital: Here are some solids. Tell me about some of their properties -- specifically which properties are unique to some of these solids.

Ayal: I would say that there is one set of solids including the cylinder, cube/oid and prisms which are like a 2d shapes that were "streched to be 3d". the word Symmetry got me to think about cutting things, so besides the sphere and the cube all solids, when cut by a plane have one part stay the same type of solid :D

oh! and another thing! the cone, cylinder and sphere can be created by taking a triangle, square and circle and spin them around themselves to a 3d shape..

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Avital: Those are all very interesting observations. Now try to imagine (or perhaps actually create) these solids as real physical objects. Play with them a little. Do you notice anything additional?

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