It’s been a dizzying rise for Simon and Nikolai Haas, 29-year-old fraternal twins reared in Austin, Texas. Just a few years ago, after relocating to Los Angeles, Simon was cooking in a vegetarian restaurant while Nikolai played drums in a band. Today they’re design-world phenomenons, the latest evidence of which is their marvelous handiwork at the new Ace Hotel Downtown Los Angeles, a renovation of the historic 1927 United Artists building and theater, an ornate Spanish Gothic-style landmark commissioned by U.A. founder Mary Pickford. Alex Calderwood, the visionary behind the Ace Hotel group (who died in November), along with lead project designer Roman Alonso, of Commune, invited the Haas brothers to bring some of their magic to the property’s ground floor. Using graphite pencils on the freshly plastered walls, they created witty cave-painting-like hieroglyphs, depicting popular history in Los Angeles and Hollywood. The brothers also crafted a stunning reception desk from reclaimed paneling original to the building, which they treated to look worm-eaten. Into this they set 15 oil paintings of palm trees in fog. Creativity runs in the family. Their German-born father, a stonemason, and mom, an opera singer who turned to screenwriting, made contributions to the Ace, too. (She fashioned an altar out of seashells for the ladies’ powder room.) "Our parents are super-eccentric, so we were exposed to lots of ‘interesting’ things,” says Simon. After moving to Los Angeles, the brothers’ aptitude with wood, stone, metal, and other materials was noted by their circle of stylish friends, some of whom they met through their elder brother, Lukas, the actor. In late 2010, they opened a woodshop that also doubled as Simon’s apartment. Commissions began pouring in. "Next thing we knew, we were in Donatella Versace's office,” recalls Simon. "We showed her a bag of samples, and she kind of flipped out.” Versace commissioned the Haases to design a collection of furniture in black leather and gold. Their client list soon included Lady Gaga, for whom they designed costumes, and Peter Marino, who had them craft fixtures for a Vuitton store in Shanghai and the Guerlain flagship in Paris. The brothers related to Marino’s biker wardrobe. "Niki and I are both really into leather,” Simon continues. "We like to bring eroticism into our work. We feel a lot of design today is kind of devoid of human qualities like humor and sexuality—and some gnarly-ness and grossness, too.”