CORECTION ALERT:

I misspoke during this Q&A while talking about polyrhythms (high-minded way of saying that I screwed up a definition).

I said that a hemiola was a polyrhythmic figure that stretched over the bar-line (ie, takes more than one measure to come around).

This is entirely wrong!

A Hemiola is simply a 2 against 3 feel (also called a duple feel). It’s basically a small polyrhythm of 2 beats against 3 beats in a measure. You can think of 3 quarter notes vs 2-dotted quarter notes (like playing a 2-feel on a waltz).

The thing I was referring to is simply playing a rhythmic figure ‘over the barline’ (doesn’t naturally turn around on the 1 of every bar.

D’oh! Learn something new every day…. Apologies for any confusion