$size = 25; $x = (xvals zeroes $size+1,$size+1) / $size; $y = (yvals zeroes $size+1,$size+1) / $size; $z = 0.5 + 0.5 * (sin($x*6.3) * sin($y*6.3)) ** 3; # Bumps imag3d [$x,$y,$z]; # Draw a shaded surface