Our house was built in 1928 and, for the most part, the original floors are in great shape. The above is a noted exception where some event of history has gouged a not insignificant chunk from the board at the joint.
The above is also exactly where some kitteh deposited their most recent hairball. Lovingly, it would seem, and overnight so that the soggy wad of fluff had time to really fill the crevice before human discovery the next morning.
I now have a positive model of that crevice made of cat hair, if any jewelry makers out there are interested in starting a line of construction-related lost wax obliquely cat centric baubles.