Just before Christmas, I spotted something curious across the street from our building in downtown Dallas: two men riding up the block on unicycles. Our city is still not known for its friendliness toward bikes. On that same stretch of Ross Avenue, I’ve seen drivers bullying cyclists with their fenders and middle fingers. So seeing these two casually pedaling up the street seemed only slightly less surprising than seeing Bigfoot galloping past on the back of a unicorn. I wasn’t in Portland. I wasn’t even in Oak Cliff. I took a photo with my iPhone and posted it on our FrontBurner blog.

Soon enough, a commenter revealed the identity of one of the riders: Darrel Green, an employee at Richardson Bike Mart’s flagship store in Richardson. It turns out that seeing Green tool around on his unicycle is not rare at all. He rides every day, up to 30 miles if he’s on the big-wheel version I saw him riding (about the size of a normal bike, albeit cut in half ) and not one of the smaller models (the kind on which you might see a circus clown). He often rides from Addison down to the Katy Trail and into downtown.

It was fitting that I saw Green when I did; he says he started riding unicycles around Christmas seven years ago. “We started selling so many of them here,” Green says, sitting at a table in the break room. “Everybody kept saying, ‘How do you learn to ride?’ So I said I’ll take it home and learn it. Big mistake.” He laughs.

It took him five days to learn. “But it’s a pretty serious five days’ worth. You keep falling down and falling down and falling down until it’s, oh, wait, I think I’ve got something here. But it was the most fun learning process. It was the best workout I’d ever had. I used to think I was in shape riding bicycles, but you don’t get the ab work you get riding a unicycle. You’re steering and balancing all through your core.”

Green has the wiry frame and permanent tan of a hard-core cyclist. And he is—just on one wheel. Since he started riding unicycles, Green rarely rides bikes anymore. He rode one this morning “over to get doughnuts and back, and that’s it.” Occasionally, when a big storm rolls in, that means he has to leave work early. But Green is committed to his singular choice. There is something almost philosophical about it.

“You gotta keep learning all the time on a unicycle,” Green says. “You never quit learning on them. I’m seven years into it, riding four hours every day, and I still see progress.”