When you drive a car, you risk getting into an accident. When you drive a time machine, you risk messing up history. When you drive a car-time machine you risk getting into an accident with yourself.
I had an entirely different strip planned this week, but scrapped it because it was something like three times the length of what I had time for. I was also concerned the payoff wouldn't be worth the time investment. Below are some of the pencils.
I hate to say too much, because I sometimes end up recycling previously-unused ideas....