Before last weekend's Indianapolis tabletop gaming convention Gen Con, I was skimming lists of the weekend's most anticipated games and seeing the same-old, same-old: a feudal japan card game, a fantasy role-playing campaign -- but a ubiquitous outlier kept catching my eye: Photosynthesis, a game about growing trees. Halfway through Gen Con's first day, attendees had greedily snapped up every one of publisher Blue Orange's over one thousand available copies.