"Found in a friend’s house in PA. Six inches tall, breaks down into two distinct halves. Made of wood with leather straps, no buckle or snap."
A: "It could be a teaching tool for demonstrating the formula for area of a circle. When she [grandmother] first started teaching in the 1920s and 30s she taught in a one-room schoolhouse, so she taught all subjects. Later on she taught reading for 4th 5th and 6th graders."