every' :: Int -> Int -> (Pattern a -> Pattern a) -> Pattern a -> Pattern a
every' is a generalisation of every, taking one additional argument. The additional argument allows you to offset the function you are applying.
every' 3 0 (fast 2) will speed up the cycle on cycles 0,3,6,… whereas
every' 3 1 (fast 2) will transform the pattern on cycles 1,4,7,…
With this in mind, setting the second argument of
every' to 0 gives the equivalent
every function. For example,
every 3 is equivalent to
every' 3 0.