The church from that article is pretty close to where I live, so a bunch of us got together and drove out there one sunday. You could indeed see a design in each window that looked like a cross.
If I didn't know otherwise, I would have said the image came from the design of the window, instead of something supernatural. That may just be the practical side of me, because I've built houses most of my life and I've installed countless windows, so I know windows.
The only thing I couldn't figure out was, if the crosses were there because of the way the window was made, how come nobody noticed it before? I mean it was a fairly old church, and apparently these crosses just appeared one day.