Not all artists stick to typical materials to create their art — some push the boundaries of what defines a medium. Here are a few of our favorite works of art made of unusual materials, curated from our BMW Art Guide archives. Which material is the most unique? __ 1. AREVALO, SPAIN Carol Bove, Untitled, 2011. ©Carol Bove, Courtesy Galerie Koch. MATERIALS: Peacock feathers on linen 2. LUCCA, ITALY Alex Da Corte, Bubble Gum Coronet, 2015. Courtesy Collezione Nunzia e Vittorio Gaddi; Lucca, Italy. MATERIALS: Powder coated saw horses, plexiglass shelves, anodized metal frames, suede, corduroy, milk glass candy dish, fur, styrofoam head, Christmas ornament, sequin pins, hair conditioner, shampoo, armature wire, rubber Milk Drop coronet bowl 3. MIAMI, USA Anselm Kiefer, Geheimnis der Farne, 2007. © Anselm Kiefer. Photo © White Cube (Jon Lowe). Collection Martin Z. Margulies, The Margulies Collection at the Warehouse. MATERIALS: Clay, argile, ferns, emulsion and concrete 4. MUNICH, G...