Ok, I'll bite
The green triangle is much smaller than the red, so when their positions are reversed, it frees up more space along the bottom section nearest to where the green triangle now lies in the second picture. Also there is now less space near where the red triangle is placed at the top of triangle. The inner designs have changed in placement to compensate for the movement of the triangles and their different sizes.
EDIT:
Had a couple of goes at this.