-- | Get the size of the bounding box, that is, the vector from the (component-wise)
--   smallest corner to the greatest corner. An empty bounding box has 'zero'
--   extent.
boxExtents :: (Additive v, Num n) => BoundingBox v n -> v n
boxExtents (BoundingBox l u) = u .-. l
boxExtents :: (Additive v, Num n) => BoundingBox v n -> v n
boxExtents (BoundingBox l u) = u .-. l
boxExtents (BoundingBox l u) = u .-. l