Where do you get work and submit solutions?

[Bitcoin]

Where do you get work and submit solutions?

is it possible to get bitcoins using your own custom code? Is it possible to get a hash somewhere, come up with a solution on my own, and then submit the solution somewhere? I just thought the puzzle part of bitcoin sounded fun, I don't want to have some other person's solver running on my machine.

Source: Where do you get work and submit solutions?