Has anyone here looked at Peter Liljedahl's Building Thinking Classrooms? Part of this is to get students up on their feet workinbg in small groups in front of Vertical Non-Permanent Writing Surfaces (aka whiteboards). It seems to me this could be something of a challenge in a traditional-sized classroom with 25-30 students, even if there are some whiteboards available around the sides of the room. I'm keen to hear of any experiences people have had -- what worked well, and what were some of the challenges with this approach to learning?