surface cellnoisy(float scale = 1;)
{
    float uu = scale * u;
    float vv = scale * v;
    setcomp(Ci, 0, cellrand(uu, vv));
    setcomp(Ci, 1, cellrand(uu + 123, vv + 234));
    setcomp(Ci, 2, cellrand(uu + 345, vv + 456));
    Oi = 1;
}