Scott Weaver’s “Rolling Through the Bay” is nine feet tall and seven feet wide, i.e. both taller and wider than my bathroom. It’s got four different paths for ping-pong balls to roll through it, tracing “tours” of various San Francisco landmarks. It took 3,000 hours over 35 years to finish. And it’s made of nothing but toothpicks and Elmer’s glue.

Still photos are pretty impressive (more here), but to get the full scope of “Rolling Through the Bay” you absolutely must watch this video of Weaver leading ping-pong balls down his different tour routes. It kind of has to be seen to be believed — and if you’re near Baltimore and you hurry, you can see it in person at the American Visionary Art Museum until Sept. 2. I will see you there.