[B]usiness students are trained to find the single right plan, right? And then they execute on it. And then what happens is, when they put the marshmallow on the top, they run out of time and what happens? It’s a crisis. Sound familiar? Right. What kindergarteners do differently is that they start with the marshmallow, and they build prototypes, successive prototypes, always keeping the marshmallow on top, so they have multiple times to fix when they build prototypes along the way. Designers recognize this type of collaboration as the essence of the iterative process. And with each version, kids get instant feedback about what works and what doesn’t work.