scale_t :: Point -> Transform
scale_t p = (scale p, scale p')
   where
      p' = inv p
      inv (x, y, z) = (1/x, 1/y, 1/z)
scale_t :: Point -> Transform
scale_t p = (scale p, scale p')
   where
      p' = inv p
      inv (x, y, z) = (1/x, 1/y, 1/z)
scale_t p = (scale p, scale p')
   where
      p' = inv p
      inv (x, y, z) = (1/x, 1/y, 1/z)