LMOrigami24 Sonobe 12 piece Octahedral with variable pyramids

Topic:
Pyramid
Page 24 of “Learning Mathematics with Origami” by Tung Ken Lam and Sue Pope published by the Association of Teachers of Mathematics

Interaction

Move the big red dot to set the heights of the pyramids.

Why doesn't the construction work well when the pyramids are reentrant? How could you improve the construction?