![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhkIIW-Z2u4wlXOiEgd6Df_u0Z3rdKbnRI55T-2kYEOrhEUPtjx8mPmzovrs58l_x0wwUJzMXF2Wlz1Vqi47miEISAbnp6Gss9hNP3lP-RxXg1RrfqwkyvBz7TrSVrGNKnivxYRCGLRSWbn/s320/a7.JPG) |
Dodecahedron |
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvcqOGKZiGQqdf5tBNQpoN81g9U8yeYzRO_fKzKwKewb1CaADdLqkkfSKGf-1pcxbB4Kg26aTM-F7wE2Kp-oScpS2LCFixz_iL3EGU2tYrY8j94TAZ8q8bsvM5SooQiBZ9b5pqoGecTldX/s320/a6.JPG) |
Reinforced Octahedron detail
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTxgcUriw8r4DisAj_Cky-2Wbe6BXndq6-e0-tg-Ln-ZkbZX7kEBsySU8GaRnZkaW21FjLjH7e9-bvH7wzjUrfRTnKcpV937cuhwPu9DVxPP9pYYbQ72_MgAxRtJ9gRS5c3TDGukDT9Cgc/s320/a5.JPG) |
Reinforced Octahedron
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgczWzAJZfo6SYGO90SbkC1cOr-f4HOqf5z8Leu0r9MhnViCZu8AQNRkdKhlANTzUAPGxZtfyvk0mFDkNclT0zXfvE30mW30u8kObuHc7HIPi5I3zYGk8HP4xUxcRVh1nzVlFdo3HI3Xli/s320/A4.JPG) |
Solidworks screen dump showing diameter which fits with 120mm diameter cd's and a 12.5mm distance between cd edges and polygon edges.
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitDy7mOBagbPZ_Vosd6j13tkVBHJjt4v3ctqrFX-7wJGUDyMSlA964L94oVubo5yLkQeIXT9bYI8RcKTKH7bmdtN82EV37u3nrupcEnETGMAfJxnUKQKXnCgRmzQAmd5JnwnPQR3ddWc3W/s320/A3.JPG) |
Truncation shapes and side lengths for the polyhedra made from the kit.
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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQBENhURPOcxfVjhOAY8AdWAcagjY7Q8egvWFUgHihWq1wd4l4dI8pLCZfMrmkbCYy1mzYYPPZXez2Bt8qSEATqOM0gj8ydD-g33wndAXYkv2dfc1ck06texJfvg9qdxQozBBRd6GR1f5L/s320/a2.JPG) |
Tetrahedron stack. From the bottom, the joins are shared edges crossing
at node, shared face, shared truncation edges. Bit of dowel in the
middle helps support it. |
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhB_swI3EP51RDxl52d8HcO0SbRlfSub633S1FShIlSeZAJucPaKrdoCcpZ6oD8Rvh2g0knJw3ViRn5Zs8tgpMTaSziHyWHfuS6bLZ0zG8EcFJr_lyCiEKz9J21-ywV5vgGUl6zzrm11d7a/s320/a1.JPG) |
Dodecahedron |
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0GZKf-vncF7ZNEDTVQUwqKGGSOTwj_bv9oNNN6yYfZ2NpTtCVVRLajPbFjHGOp5lxOkQ_DCrNONwbRZ90PSXdRD9-mOuO-E5-su87DdUQ2PRc7k_4KagypNS_QYF9oqnG03wpD8Qd1I4p/s320/a8.JPG) |
Calculation spreadsheet screen dump. The actual spreadsheet can be found here.
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Hi
This post is bit of a carry-on from the previous one, and at least some of the pics in the previous post apply. I've released the STL file for a single piece construction kit which uses CD's, rubber bands and 2.6mm bamboo rods to make constructions - all the regular polyhedrons plus tessellations and other forms. This post is a bit of a pre-hack, writing down and drawing the geometry required for forming truncation sides in the construction. I've already done some work based on the hacks, making a truncation side for an octahedron which makes this construction more secure.
It does this by joining some sets of 3 sides to each other making a rigid form not present in most of the "pure" octahedron subassemblies. The square side construction is made from a bicycle rear cog.
Up till now I've made cubes, tetrahedrons, octahedrons and dodecahedrons using the cds-as-sides-method. I haven't been able to make icosahedrons yet but have a few ideas.
Happy Constructing, Regards Steve Nurse
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