MeshPatch
class MeshPatch(val x: DoubleArray, val y: DoubleArray, val colors: Array<RgbColor>, val t: DoubleArray? = null)
One patch of a type 6 or 7 mesh as a tensor-product surface (ISO 32000-1, 8.7.4.5.8). x and y hold the 16 control points in shading space, p(i, j) at index 4 i + j, and colors the colours of the corners p(0,0), p(0,3), p(3,3) and p(3,0). A Coons patch of type 6 gets its 4 interior points from its boundary, by the equations of 8.7.4.5.8, and the tensor-product surface of those points is the Coons surface.