Does the same effect happen if we do something completely un-related to math like increase a font-size in the middle of a line? Oh-ho--discovered since e-mailing you, Eric, that if you set line-height:0 on the inserted stuff it behaves as you'd like it to.

What do we mean by rotation?

If a rotating body has one point fixed, let's call it the origin `O`, then it's possible to imagine rotation happening through only one axis, or direction at a time, specified by a unit vector `myv(u)` at a rate `omega=(d theta)/(dt)`. Usually we combine these two to write the angular velocity as a vector

`myv omega = omega myvu`

where the direction of `myvu` is given by a right-hand rule.