It's a lovely shot, and well processed, but I don't think it meets the challenge. I'm not sure if you are referring to the typewriter as something that creates letters (which misses the challenge completely) or insuating that the buttons represent "O's", but either way I just dont think it meets the challenge. But again, in general, it is a very nice photo.
I was under the impression the pictures were to contain letter that were made by you from props, I see the correlation with your picture. But I do not think you made this antique keyboard.
As far as the shot goes, I like the DOF and normally I would complain about the dust and cobwebs, but since it is an antique I think it adds to the picture.