One of my long-time favourite programs for RISC OS is !PolyDraw from Fortran friends. If it is not already installed on your RISC OS machine, it deserves to be (shame on you). It is fast, fun, educational (and since 2016 it has also been free). It also has that wonderful property of a great game - you can use it pretty much instantly without the manual but it has loads of depths to explore.
 
!PolyDraw and its linked programs (!PolyNet, !Stellate and !PolySymm) lets you view, create and explore complex mathematical shapes. It also lets you print out the flat design for any shape which you can then cut out and stick together to make a physical shape.
 
The software gives you a huge range of three dimension shapes, which you can inspect in a 3D viewer. The viewer lets you choose how to rotate the shape in any directions, what color/shading you use (or you can stick to wire frame) and shows the flat outline net of the shape. When you print them out, the software adds tabs to the surfaces so you can cut out and glue the shape together. If the 141 initial shapes are not enough, there are additional data sets to load and use can create your own.
 
At RISC OS shows the Fortran Stand is usually full of Cubes, Dodecahedron and other icosahedra and the experts show you how to use features in the software. It's like being back in your coolest ever Maths class! As they say it is ideal for children of all ages (especially those over 18).
 
They are regular exhibitors at the South West Shows. So hopefully you will be able to see them in a few weeks.
 
All details and their downloads are on the Fortran Friends website.