On a scorching 100-degree day, I find Henry Dorado’s booth at the Brooklyn Flea Market. Above, trains rattle loudly on the Manhattan Bridge. The outdoor market is a small but trendy event that fills this corner every weekend, rain or oppressive shine. Among the typical antique market wares — racks of thrifted clothes, watches behind glass, bins of art — Dorado’s booth stands out. People slow down, sometimes chuckle, take photos, and summon friends over to look at all this. A crowd surrounds the modest shop...