Interesting. Maybe there was more than one effect going on here. What I saw looked like what is shown on the link you posted, except there was no change in size or intensity between light spots, which I can't explain. Just a column of perfect circles. Hmm...
I admit I actually cannot...
Diffraction pattern??
This isn't a homework problem, but something I noticed and would like to understand. Hopefully I have posted this in the right area:
I have a window that faces west. The other day I noticed a perfectly circular patch of light (several inches in diameter) on the wall...