Okay, this is cool. From ReadingMate:

Though reading could be a useful activity for joggers running on a treadmill, reading while running can be quite tiresome especially to eyes. Since the relative location of the eyes to the contents (i.e., the text) is vigorously changing, our eyes must constantly adjust to such changes, which is burdensome. In order to alleviate this difficulty, we developed a infrared-camera-based contents stabilization technique, called “ReadingMate,” by using head-tracking to track the location of the jogger’s head/eyes and relocate the contents on a screen so that the contents appear to be stabilized.

Maybe not the most pragmatic thing ever -- I started thinking of what you could do with a projector on the wall before going "wait... wait, maybe not most useful interface ever to think about implementing in apartment" -- but it's an interesting look about head tracking, which is something I've been thinking about lately.

One thing I became aware of on the 2nd day of dance class (several weeks ago, now) was my habit of horizontally stabilizing my head. This makes sense; I'm more reliant than most on fine-tuned visual input (lipreading, supplementary text). These are mostly still and vertical. Hence, my head is still and vertical, even when the rest of my body is moving -- a habit I'm breaking now in my motion, deliberately. There's still a moment of slight fear when I let my head go out of vertical and spin around: wait! You'll miss something! But I know I've put myself in a situation where there's nothing to miss.

I wonder what I can do to make this more of an environmental factor, a habit of sorts, in the places I'm in. Hanging worksheets/instructions on my wall off-kilter might be a start, so I actually need to lean (with good body alignment -- consciousness!) to read them properly.