Some lenses have oddly shaped apertures, like star or shuriken shaped. It seems to be intentional since making "normal" rounded or polygonal apertures is fairly simple (as I have observed while disassembling the irises of several lenses). What are the technical reasons to make apertures that way?
I recall reading a comment somewhere that it's done to correct for some lens defect, but have been unable to confirm. Usually, the blades look like they could be extended slightly to avoid the pointy corners, so it's unlikely an alignment issue.
I am not asking about apertures shaped by the photographer artistic effect.
From a rebranded 35/2.8 manufactured by Tokina.
From a 35/1.7 C-mount lens.