You can also throw someone in a swimming pool and if they sink, they might be African-American. And I’m not joking!
Okay, true story: when I was in college, everyone was required to pass a swimming test or take a swimming class. So all of us freshmen were at the deep pool one day to take the test, which required jumping into the 16-foot deep pool, treading water for some set number of minutes, and then swimming to the other side and back - didn’t matter how, doggy paddle, etc., as long as you went out and came back. This one poor girl was absolutely petrified. She showed up wearing a swim cap, earplugs and a nose clip, and she was trembling. The instructor kept telling her she did not have to do the test...it just meant she would have to take the class instead. She insisted on attempting the test, even though her teeth were chattering from fear. She jumped in and sank to the bottom of that 16-foot pool like a stone and didn’t come back up. We were all amazed. “Why didn’t she push off from the floor?” Three lifeguards were in right after her to bring her up, but I think she probably would have just stayed down there if they hadn’t.