I've accomplished something I've been thinking of for a while, and finally bought a lens that will never break and will work on any camera via easily-available adapters. It's a genuine Holga pinhole for Nikon F-mount.
There's also an M-mount pinhole body cap on its way to me, so I should have both of them by World Pinhole Day, which I forgot about when I decided to order them. Sometimes things just work out.
These are just quick digital photos, but I'm looking forward to using the pinholes with film. For once the difficulty of working with the analog medium will be less than the time spent dust-spotting digital images shot at f/umpteen.