{
 usage: U*UVn and V*UVn
 refl: random tiling 
 
 A1: U tile size 
 A2: V tile size
 A3: seed
 usage:
 void mixfunc floor
 4 tileA tileB refl uvn.cal
 0
 3 5 5 10

}
UVn = if(and(Nx^2+Ny^2-FTINY,Nz^2-FTINY),sin(atan(sqrt(Nx^2+Ny^2)/Nz)),1);
Utno = frac(floor(UVn*U/A1)/A3)*A3;
Vtno = frac(floor(UVn*V/A2)/A3)*A3;
refl = if(rand(Utno+Vtno*A3)-.5,1,0);

