So have you worked it out yet that if it is the 'same kid' he couldn't be 'David' because he's Zero - and he couldn't be sitting next to Mark (as Mark claims) because Mark was born after his mother and father married on Christmas Eve, 1964? Have you worked it out that the older, darker boy, is the son of the kenyan student, and that Ruth couldn't be his mother? Or, lol...are you still wondering how the hammer fits into the wheeled tool-kit toy?
You’re right, it wasn’t a tool-kit toy.