loopCompF :: F (Either (Either a b) (Either c d)) (Either (Either c e) (Either a f)) -> F (Either b d) (Either e f)
loopCompF
is a symmetric version of loopCompThroughRightF. When
applied to a parallel composition of two fudgets it allows the fudgets
to communicate both with the outside world and with each other.
Other combinators that operate on parallel compositions: serCompRightToLeft et al.