Instead of differentiating by font size you could differentiate by color intensity (e. g. like in http://www.artlebedev.ru/everything/clouds/linear/ http://www.

Instead of differentiating by font size you could differentiate by color intensity (e. g. like in http://www.artlebedev.ru/everything/clouds/linear/ http://www.artlebedev.ru/everything/clouds/linear/ )