ʋ - Last Four As Dyad
The resulting link is dyadic, meaning it takes two arguments. Note that the arity refers to that of the resulting link, not the number of links this quick consumes.
Combine four links (that aren't part of an LCC) into one dyad.
Scanning backwards, if the chain starting at that point is not an LCC, increment a counter. Once the counter reaches four, return those links combined into a dyad.
<link><link><link><link>ʋ- combine links into one dyad