Well obviously Bill Gates bought a time machine and came back to the past to invent blockland, duh.
impossible. if you were to travel back in time to a point of which you had an older or younger self living, the space-time continuum would screw itself over, you causing the wipe-out of time.
plus, if you traveled back in time at all, you are developed further than you should have been at the point in time you want to travel to. thus, the traveler itself would vaporize. (p.s., this is theory)
also i see baddy as a sentient overlord of these on fire forums.