Late to the party, wanted to comment re: doing tai chi outside -- when I drive up to NY to visit family I usually do it at night to avoid traffic. I generally stop at a rest stop on the Jersey Turnpike around midnight - 1 am-ish. Some years ago when I stopped there I saw a man standing in the middle of the parking lot doing tai chi. I usually need to do some stretching by the time I reach that stop, standing in front of the sinks in the ladies room, so I totally understand why someone would want a tai chi break during a long drive. It was an unusual sight but not the strangest thing I've ever seen.

(I am not walking at all these days -- I'm lucky if I can run errands without ankle pain. With the beautiful weather we've been having, I would love to get out for a stroll around my neighborhood to see the flowering trees.)