With the Genie it's a step change that occurs when the stroke of the shock is big enough for the additional ports to be closed off. With the Aria, a triple chamber shock (same tech is available in forks), the spring is a continuous curve that is adjusted. You could very likely achieve a very similar effect with a triple chamber shock, depending on the size of the chambers and the pressures set in the two chambers, but it's a lot more finnicky for the end user and requires a lot of playing around to get the desired effect (without...