@FIRST_LIGHT

Thanks! I hope to make it to Szeged, but it's 50-50 at this point.

I think the grid is chronological from left to right, top to bottom. White boxes show no sentiment one way or the other (e.g. "I am creating a Drupal theme today."). The greenish or reddish boxes show positive or negative sentiment (e.g. "I love/hate creating Drupal themes!"). I think that's how it works.