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. And so all these red cells eventually make their way around the green structure, around the blue structure and ultimately around the entire trophy blast, the purple section of this diagram. And so when we go from diagram four to diagram five, this is what we produce. So this imagination process along the primitive streak, the movement of the ectoderm cells into the red section, the formation of these red cells eventually pushes all these red cells and the mesodermal layer around the green structure, the blue structure and around this entire purple structure to form the following diagram.