Clifford Torus — 4D Projection

T² ⊂ S³ ⊂ ℝ⁴ — stereographic projection to ℝ³

Clifford torus: parametrized as
(cos u, sin u, cos v, sin v) / √2 ⊂ S³ ⊂ ℝ⁴

It is a flat torus — intrinsic curvature = 0! Unlike a donut embedded in ℝ³ which is curved.

Stereographic projection from S³ to ℝ³:
(x,y,z,w) → (x,y,z)/(1−w)

As the 4D rotation sweeps w, the projected shape morphs continuously between a torus and two interlocked circles (Villarceau circles).

Drag to rotate the 3D view. The 4D plane control picks which 4D rotation to animate.