This would indeed be hard. One way I could see it done was introduce a special symbol as repeat limiter similar to what i does for slider continuation legs, and thus means "as many repetitions as there were in the previous parenthesized group". Suppose that symbol is $, you could write [(mpW-)pW-(mpW-)$cW]. It is a sort of orthogonal Equihopper.
This would indeed be hard. One way I could see it done was introduce a special symbol as repeat limiter similar to what i does for slider continuation legs, and thus means "as many repetitions as there were in the previous parenthesized group". Suppose that symbol is $, you could write [(mpW-)pW-(mpW-)$cW]. It is a sort of orthogonal Equihopper.