Six months later, the "Free Craigslist Greenhouse" wasn't just a pile of parts in the driveway. It stood in Leo's backyard, glowing under string lights. Inside, those heirloom seeds Martha gave him were already six inches tall, protected from the late spring frost.

Every time a neighbor asked where he got it, Leo would smile and say, "It was free! I just had to pay for it in sweat and blue painter's tape."

He didn't email; he called. A tired-sounding woman named Martha answered. "If you can get here by 8:00 AM with a socket wrench and a lot of bubble wrap, it’s yours," she said. "The new owners want it gone for a pool." The Art of the Dismantle

: They used blue painter's tape to mark every joint—"A1 to A1," "B2 to B2."