Split increases are a way of performing width increases using the split
operation.
They are less efficient than tuck increases, and require more tuning than twisted tuck increases, but produce a nicer result than either.
In a split increase, a new loop is "created" at a location by splitting through one of the loops adjacent to that location, then transferring this loop to the new location. This can be done during the process of widening the fabric or as a separate operation after transfers are used to create an empty space for the new loop.
Split increases can be twisted.