Lots of things were for sale in the front yard, a whole house had been turned out. I walked slowly, not intending to buy anything, just passing time.
Something caught my eyes; a large oval mirror that was reflecting a wooden shack with trees. I looked around but there was only red brick houses and clipped bushes.
I picked up the mirror, the view didn’t change. A painting? No, it really was a mirror but the reflection of that shack was trapped inside.
I brought it for two bucks and it’s still a mystery to me today.
(Inspired by; https://rochellewisoff.com/2018/08/29/31-august-2018/ with thanks.)