OmniFocus and classifying things by available energy level

[John SJ Anderson]

A while back -- but within the last year, I _think_, I read an article
describing using OmniFocus in such a way that one of the axes items
were categorized on was energy level -- I think by using the 'context'
axis in a non-context-y way.

I'd like to re-read this, but my Google-fu is failing me. Little help over here?

thanks,
john.