That is a pretty interesting picture, what were you shooting, the sun? It reminds me of looking through my eyelashes. Your livingroom shot is interesting too, because it shows off the shape of your aperture, was that the one you made with an awl? It's pretty distinctly not round.

Neat! Do you know those cookie guns, like caulk guns, but with little metal plates at the end that extrude cookies in different shapes? Your three pinhole experiment makes me want a set of pinhole plates, you could have the smileyface pinhole, and the triangle pinhole, etc. Really, it would be the most fun if you could replace your lens aperture with one of these plates, then you would get better focus on the subject, and the bokeh would be creatively interesting, rather than a polygon approximating a circle.

Busy busy busy.

I guess I was really thinking about the shape of the blur circle rather than the bokeh, which would just come into the image as a convolution. Good bokeh is gaussian, and the Fourier transform of a Gaussian is another Gaussian, so in that case Fourier transforms are sort of involved, but in general with a pinhole wouldn't your bokeh just be a simple convolution of the pinhole shape, since there is no contribution from spherical aberration? I don't see where the Fourier transform would come in.

And, yah, if you gave your pinhole soft edges it would probably cut down on diffraction. Tried it yet?

The fresnel zone plate is pretty interesting, couldn't you make one that was multi colored using slide film? Print the ideal plate for green with magenta, the ideal plate for red light in cyan, and the ideal plate for blue in yellow? I vaguely understand how it would act as a lens, but diffraction still seems pretty esoteric to me. Now I want a multi color starfish pinhole fresnel lens... but I probably wouldn't use it.