Schwartz 'D' Sphere, 8 cell

The Schwartz 'D' surface is another triply periodic minimal surface like the gyroid. 8 of the unit cells are put together here, but only within a radius 2 Pi sphere). Equation of this trigonometric approximation to the true minimal surface is: Sin [x] Sin[ y] Sin[ z] + Sin[ x] Cos[ y] Cos[ z] + Cos[ x] Sin[ y] Cos[ z] + Cos[ x] Cos[ y] Sin[ z] = 0 Like the gyroid, this surface also appears in nature, frequently in oil/water surfaces where the oil separates the water into two domains at the microscopic level.