Collapsing anchors is the process of anchoring two different states – one negative and one positive. And both are fired at the same time, allowing the positive state to neutralise the negative.
Stacking anchors is the simple practice of anchoring more than one positive or resourceful state on top of another. This increases the power of the anchor.
Chaining anchors is a process whereby you create a link of anchors to move someone from an undesirable state to a distant more positive state.