Abacus
Just for fun, I made one of these and gave it to my Accountant as a gift. No plan to follow, just looked at a picture. He got quite a laugh out of it and keeps it on display in his office.
Made with 3/4 inch solid red oak and 1/8 inch oak plywood. The corners feature a rabbet butt joint.
The beads were bought predrilled and finished with a walnut stain. I think the built in sliding cover came out pretty good.