Call it an exercise in sole-idarity. Noted Chicago-born shoe designer Brian Atwood has joined forces with his younger brother Zak Rodriguez to create limited-edition women’s footwear. The brand’s name, Il Fratellino (Il Frat for short), is Italian for “little brother” — a college nickname Brian’s friends gave Zak. The duo wants wearers to have fun in these shoes. “Every pair is designed to have incredible energy and made for a big night out,” says Zak, who still lives here. The shoes are dreamed up by the brothers, handcrafted in Porto, Portugal, and sold only online. The first collection, priced from $250 to $490, dropped last spring. When new styles arrive each season, you have to snag them fast before they’re gone. Currently up for grabs: silk mules with custom-dyed ostrich feathers (pictured; $490), bold metallic booties and heeled sandals, and white Italian leather sneakers.