Concrete squares in yard
There are three concrete squares in my yard that I can't figure out. They are all the same size, 17 inches square with a 9 inch square open space in the center. They appear to have been set in a straight line down the center of the lot side to side. On is on the edge of the front porch, one is approximately in the center of the yard front-to-back, and one is at the rear of the property.
The house was built in 1919. Any idea what these could have been used for?