Stereos (Greek στερεός: solid, three-dimensional, firm). The solid as pure number: a polyhedron held as vertices on the unit sphere and faces wound counter-clockwise seen from outside, with the winding made impossible to get wrong — every face whose normal points back toward the centre is reversed at construction, so a back-face cull is honest by shape rather than by careful typing. It holds the five Platonic solids (the dodecahedron derived by duality from the icosahedron, its pentagons ordered around each vertex by angle so they are drawn as pentagons and not as stars), the pentagonal trapezohedron a real ten-sided die actually is — its apex height solved from the condition that each kite be planar, never chosen by eye — the barrel a real three-, five- or seven-sided die is cut as, which declares itself unfair out loud because its side faces are equally likely while the shape is not face-transitive, and the disc, which is a coin and says so, its rim built and lit and never numbered. Beside the shapes stands the light that shows them: one house light so two surfaces can never disagree about where the sun is, an ambient floor generous enough that a face turned away reads as stone in shadow rather than as a hole, a perspective divide that hands back the depth it sorts by, painter's order, Lambertian shade and a Blinn-Phong highlight. The self-check RETURNS its complaints rather than throwing them, because a design system that breaks eighteen apps on import is worse than one that says what is wrong. No colour, no rendering, no DOM, no disk, no clock, zero imports: numbers in, numbers out.
Greek στερεός (stereos, solid, firm, three-dimensional); the name states the atom's own claim about its subject, shapes held as pure number and checked by geometry rather than by the eye.
The solid held as pure number rather than as a picture: vertices, faces, and a winding order made impossible to get wrong by construction. What it renders is checked by its own geometry before anything is drawn.