quantum mechanics - Why is lens flare doubled if odd number of blades but equal to number of blades if even?

An article in Picture Correct describes how the number of blades in a particular lens correlates to the number of starburst points associated with lens flare. The number of starbursts is double the number of aperture blades if there are an odd number of blades and equal to the number of blades if the lens contains an even number of blades. Here's a jpeg of the article should the above link ever break:

What property of light could cause this phenomenon?

_{This seems more appropriate here on the Physics page than it does on the Photography SE community, since the question is about the physics behind this and not whether or not it's true.)}

Answer

A straight edge causes diffraction in the direction perpendicular to that edge. When two straight edges are parallel to each other their diffraction patterns will overlap (point along the same line) - making it look like there is just one.

That happens when there is an even number of blades.

Note - I believe the diagram for the six pointed blade is wrong - it shows the flare aligned with the corners of the hexagon. I am pretty sure they align with the centers of the blades instead. (Note - for an odd number of blades the distinction cannot be made).