You can chase a virtual butterfly in a simulated elevator. Or try to sink a battleship. Or pop the bubbles your opponent is blowing through a wand. A UC Berkeley class opened its doors to the public yesterday to glimpse the future of interaction — at least as imagined by the students in the course, reports the San Francisco Chronicle. It will be the second open house this week for the 11 final projects in "Theory and Practice of Tangible User Interfaces," a title that in theory is off-putting and in practice is fun. The first open house, on Tuesday, transformed a venerable classroom in 135-year-old South Hall — the oldest building on campus — into a noisy and chaotic mix of science lab, video arcade and children’s playground, full of Zen moments, tangled cords and makeshift projection screens. "Students are really trying to apply what they’ve learned," said course instructor Kimiko Ryokai, 33, an assistant professor in the School of Information at Cal. The goal, not always met, was to come up with concept-driven designs and devise solutions to future problems that people might not even anticipate.