Oops. Looks like the mods added it.

Also, apparently previously discussed - http://news.ycombinator.com/item?id=1503860

I'm glad that set of comments called out the pendulum staying in a plane as being wrong. Like the article says about gyroscopes, tilted pendulums move in an odd but predictable way. For example, a pendulum set up on the surface of the earth rotates at a speed proportional to the sine of the latitude.

Does this diminish or enhance the value of the article in any way?

It's customary.