9 December 2025
Last week I saw Hamerschlag Hall through a window at the Carnegie Museum of Art. Actually, it was an optical illusion on one of our rare sunny days, reflecting CMU’s iconic building perfectly. (The milkweed pods are in the garden in front of me, not reflected on the window.)
The Hamerschlag optical illusion reminded me of Venus on the clamshell whom I saw last year at the Carnegie Museum of Natural History just across the parking lot. Here she is in a photo with 1 Inside and 2 On-the-window images.
- Inside the window: Two giant clam shells are in the room behind Venus, faintly showing behind her.
- On the window: Venus is a sticker on the window + there is a reflection of the Museum of Art building as well.
We are not the only ones fooled by glass reflections.
This window at the classroom building at Mass Audubon’s Wellfleet Bay Wildlife Sanctuary looks like there is sky and open grassy space on the other side. For us, the bottom panel is dark because it reflects the pavement.
But for a bird flying close to the ground the bottom window reflects the grassy space. A small bird was fooled by this illusion and crashed into the window, leaving his imprint.
I hope the bird survived.
Sadly these optical illusions are why glass kills one billion birds every year in the U.S. That’s 2.7 million birds each day.
p.s. The lady at the front desk at Mass Audubon said they know about this problem, which is more extensive than the door, but have not had the money to solve it yet.