unionBounds :: Bounds -> Bounds -> Bounds
unionBounds (Bounds la ta ra ba) (Bounds lb tb rb bb) =
  Bounds (min la lb) (min ta tb) (max ra rb) (max ba bb)
unionBounds :: Bounds -> Bounds -> Bounds
unionBounds (Bounds la ta ra ba) (Bounds lb tb rb bb) =
  Bounds (min la lb) (min ta tb) (max ra rb) (max ba bb)
unionBounds (Bounds la ta ra ba) (Bounds lb tb rb bb) =
  Bounds (min la lb) (min ta tb) (max ra rb) (max ba bb)