For yogis who prefer a challenging cardiovascular workout, there's no better option than bikram yoga — a hot yoga class that forces your body to sweat out toxins through ninety minutes of intense balancing and strength-training postures. The class is physically and mentally exhausting — some deep backward bends may make you feel dizzy or even trigger unexpected emotions — which is why the colorful designs and inviting layout of Funky Door Yoga in South Berkeley are very welcome features. The studio's interior walls are lined with brightly colored, cartoonish paintings of humans and animals doing the 26 different poses of the class, providing a nice visual reminder in the hardest moments of the class to not take yourself too seriously. The paintings by artist Ed Renfro — including a stretching Elvis Presley, a queer Frankenstein, and a poodle mid-posture — provide a goofy and calming backdrop for the very draining class. The yogis in the drawings also model extreme flexibility and the most optimal versions of each posture, reminding participants in the class how far they can push their limits if they keep practicing.