Now, what happens is if we zoom in on this section, we get the following diagram. And what happens is we have this invagination process where the blue layer basically invaginates and informs the primitive streak. And along the primitive streak, which is basically this access where invagination takes place, these blue cells essentially invaginate and move inwards. And as they move inwards, these blue cells develop into the red cells that make up the Messider. And as this pushing process takes place, all these red cells eventually are pushed around this entire structure. So if we look at this diagram, what happens when we go from diagram four to diagram five is there is an inward push that goes into this direction and that pushes all these red cells around the following diagram.