+data Cardinal = F -- ^ Front
+ | B -- ^ Back
+ | L -- ^ Left
+ | R -- ^ Right
+ | D -- ^ Down
+ | T -- ^ Top
+ | FL -- ^ Front Left
+ | FR -- ^ Front Right
+ | FD -- ^ Front Down
+ | FT -- ^ Front Top
+ | BL -- ^ Back Left
+ | BR -- ^ Back Right
+ | BD -- ^ Back Down
+ | BT -- ^ Back Top
+ | LD -- ^ Left Down
+ | LT -- ^ Left Top
+ | RD -- ^ Right Down
+ | RT -- ^ Right Top
+ | FLD -- ^ Front Left Down
+ | FLT -- ^ Front Left Top
+ | FRD -- ^ Front Right Down
+ | FRT -- ^ Front Right Top
+ | BLD -- ^ Back Left Down
+ | BLT -- ^ Back Left Top
+ | BRD -- ^ Back Right Down
+ | BRT -- ^ Back Right Top
+ | I -- ^ Interior
+ | Scalar Double -- ^ A wrapper around a scalar value.
+ | Sum Cardinal Cardinal -- ^ The sum of two directions.