Going

Life is like a bicycle. To keep your balance, you must keep moving.

~ Albert Einstein

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In Einstein's defense, there weren't scooters like this around in his time. Otherwise I'm sure he would have said, "Life is like a bicycle and Zak's scooter. To keep your balance, you must keep moving."

I would wonder how Einstein knew Zak, but Zak gets around, so it's possible. Mostly he gets around on his scooter.

Or his bike. 

I guess you're right after all, Einstein.