Except if I were running a pulse width modulation, right? Yes, those thousands of transitions would be happening every second, but the processor would be stuck thinking about that transition and not much else. Or is that also so "slow" that other operations could still continue?
I guess the solution there would just be to drop the PWM pulsing of the brake light and go for normal on/off blink.
I think I'm slowly coming around to seeing how this is possible. Once I wrap my head around that then I should be able to program it in.