avoidMaster :: W.StackSet i l a s sd -> W.StackSet i l a s sd
avoidMaster = W.modify' $ \c -> case c of
W.Stack t [] (r:rs) -> W.Stack r [] (t:rs)
avoidMaster :: W.StackSet i l a s sd -> W.StackSet i l a s sd
avoidMaster = W.modify' $ \c -> case c of
W.Stack t [] (r:rs) -> W.Stack r [] (t:rs)