Woodworking terminology question
To make a dodecahedron, I would like some pieces of wood with a cross-section like the diagram below

but at the moment my pieces of wood are all of square cross-section. What's the name of the device which could cut such a profile, and does anyone know where to find one in Cambridge? You're looking at plane sides, so a plane comes to mind, but I don't know how you'd hold the wood to plane one corner off to a weird angle.
This is a long-term problem; I discovered on Wednesday night that I can't cut 45-degree mitres in square-section wood accurate to better than a quarter-inch, mostly out of a shortage of clamps and an initial failure to lock all the locking nuts on the mitre saw.
but at the moment my pieces of wood are all of square cross-section. What's the name of the device which could cut such a profile, and does anyone know where to find one in Cambridge? You're looking at plane sides, so a plane comes to mind, but I don't know how you'd hold the wood to plane one corner off to a weird angle.
This is a long-term problem; I discovered on Wednesday night that I can't cut 45-degree mitres in square-section wood accurate to better than a quarter-inch, mostly out of a shortage of clamps and an initial failure to lock all the locking nuts on the mitre saw.