A chopping board, cut at a sharp angle to get a useful shape and a good final surface, starting with a height of about 7cm using a chainsaw. Then, place it on a workbench and secure it by screwing it into the side. Set up two flat guides at the necessary height, and place a long enough board across them with a router mounted on top; use this to plane the rock-hard wood to a "mirror" finish. Once one side is done, flip it over and do the second. Use a chisel or the router itself to create a drip groove that ends in a drain at one end of the "ellipse".

Cut as shown in the photo, there isn't much else they can do. If you want, you can use wood carving discs (grinder discs, made like wood rasps for carving, dangerous to use, so be careful) to shape other things, for example, a stylised fruit bowl to be decorated later with a pyrography pen or chisel, but this requires much more skill than the chopping board and the practical daily use isn't great.

If there's still a long piece left and you like polenta, you can make a classic Italian "polenta stick", literally a stick about 80-90cm long, with a diameter that's comfortable to hold and a wider, flattened end. But carving it from a log requires a certain level of skill; you can even do it without a lathe by starting the cut with a chainsaw and then setting up a "DIY lathe" using a drill and a router. It's a long, frustrating job for a result that doesn't make much sense anymore now that we have self-stirring pots for polenta, but it can be done, just like you can make large kitchen spoons.