[Aaaargh!!!](http://magic.wizards.com/en/articles/archive/making-magic/aaaargh-2006-01-30-0) by Mark Rosewater

[Designing for Gruul](http://magic.wizards.com/en/articles/archive/making-magic/designing-gruul-2013-03-04) by Mark Rosewater

[Color Pie Friday: The Philosophy of Red/Green](http://sarpadianempiresvol-viii.tumblr.com/post/99053685935/color-pie-friday-the-philosophy-of-redgreen) by Sarpadian Empires vol. VIII