Simple geometry

A possible candidate for the “geometric origami” book I’m working on, although I’m not sure exactly what geometry properties it demonstrates!!

crease 4×4
valley twice to make a 4×1 strip
add one diagonal in each small square
form a tube, tucking 1 square inside
twist!

Curiously, if you view it with a corner pointing upwards, the mind suddenly interprets it as an octahedron with sections missing….