Reading the board…
Rosetta Code for B-rep kernels. Each case describes a solid in words and gives its volume and area as closed forms. Each kernel builds it in its own idioms, and every result is graded the same way; a refusal ranks above a wrong answer, and no kernel ranks above another. Open a category or a kernel for its cases, or a case for its drawing, every kernel's result in 3D, and every kernel's code.
A B-rep (boundary representation) kernel builds solids by operations (e.g. extrude, revolve, sweep, loft, Booleans, blends, offsets, shells) on geometry and numbers. It represents each solid it builds by its boundary: a set of faces that meet along shared edges and close around a volume.
For many operations, the hard part is working out where the resulting solid's surface lies. A B-rep generally stores that result in evaluated form: each face is a function S(u, v) that returns a point on the surface, as (r cos u, r sin u, v) does for a cylinder. One evaluation gives one point. The alternative is a function f(x, y, z) that is zero on the surface: it says whether a point is on the surface, not where the surface is. Finding it is a search, which takes longer the finer the answer has to be. Machining, optics and rendering all need the surface, and they read it from the B-rep instead of searching for it.
Reading the board…