Conversations on mass transit here may range from abandoned subway tunnels to Metro fares to streetcar proposals, but you can always count on a heated discussion.

Perhaps that’s why a tongue-in-cheek T-shirt featuring a “Cincinnati Transit Map for Optimists” has become a popular buy for mass transit supporters, as well as for anyone who enjoys its colorful display of connected Cincinnati neighborhoods.

Cincinnati native Chris Glass, a founder of Oxford-based design company Wire & Twine, created the shirt. Glass started the design from scratch, studying other transit maps and consulting with local friends.

“A lot of love went into that shirt,” comments Tom Duvall, who, along with Glass, founded Wire & Twine in 2006 with his wife, Wendy.

The shirt, which debuted in March 2007, continues to be a top seller for Wire & Twine. It’s sold for $25 online, as well as at Mica in O’Bryonville and at Park + Vine in Over-the-Rhine. Dan Korman, owner of Park + Vine, says that the T-shirt has sold more steadily than any other he has carried, and it always brings a smile to the face of those who see it for the first time. Many, he says, think it’s a transit map for another city until they look more closely.

“I definitely think people are interested in mass transit,” Duvall says. “And I think some people get the joke — Cincinnati is sometimes slower to embrace ideas that other cities have undertaken, although they’re picking it up now, and that’s exciting.”

This type of transit map often deviates from actual geography to promote clarity, which requires a “very generous dollop of creative license,” Glass says. So, while this design probably could function as a real map, Glass is the first to admit that a system this complex is a very distant prospect.

Wire & Twine’s T-shirts are screen-printed by hand with environmentally friendly inks and chemicals on American Apparel T-shirts, which are made exclusively in the United States. A portion of the proceeds from each shirt is donated to charity.