Mystery

Two preserved Betzwood Film Studio buildings are right next to each other alongside the Schuylkill River Trail. When I take my "long" walks, I pass them. A couple weeks ago, on one of my evening walks, I noticed something odd. There were three distinct spots of light on the side of one of the buildings. (The top one looks a little like Pikachu, don't you think?)

I turned around to see where the light was coming from. Was the other building finally occupied?

Nope. No lights were on. Well then... hmm. Weird!

Being slightly slow on the uptake, I looked back and forth a few time before I realized that the sun was at the perfect angle to hit those top three windows and reflect back to the first building.

Mystery solved.