Normal steps have two projections, one at the beginning, and the second one at the end of the step. The base leg continues to work, pushing the floor until there is no weight on it. This continued work helps to stabilize the transition to the new base leg. It also means that in the instant that the old base leg becomes free, it is actively stretching. This is the second projection.
The old base should not immediately move to the new base leg. It’s now free, which means [1] it now belongs to the leader so it must be available and not doing anything arbitrary and [2] it needs to be both extended and soft. When the free leg is stretching in this second projection, it can respond to cool things the leader might want to lead.
The second projection makes possible cross, rebote, parada, voleo, and lots of other playful things…
