These purple cells form a group of their own because they have one type of cell adhesion molecule, while the blue cells form a group of their own and bind together because they have a completely different type of cell adhesion molecule. Now, this process, for example, plays an important role in the formation of the gastrolo stage. So during gastrolation, our morphogens influence the type of cell to cell adhesion molecules that are found within our cells. And to see what we mean, let's take a look at the following diagram. So this is basically our blastula stage. So we have the trophy blast cells and we have these inner cell mass that are shown in blue.