Notched disc

The Notched disc, by unknown artist. Dark gray circular object with a large central hole. The circumference of the circle has 7 notches on each side; on the left, there are 3 large notches and 4 small notches; on the right, there are 4 large notches and 3 small notches. The notches are V-shaped. The object appears to be made of stone or metal. It is displayed on a light gray background. A small scale and text are at the bottom.