rotcell problem http://nabetani.sakura.ne.jp/yokohamarb/2014.10.rotcell/ pair programming session at yokohamarb http://yokohamarb.doorkeeper.jp/events/14228 How to run ruby rotcell.rb other answers http://qiita.com/Nabetani/items/d6ac6695787e76758a18#%E3%83%9A%E3%82%A2%E3%83%97%E3%83%AD%E3%82%BB%E3%83%83%E3%82%B7%E3%83%A7%E3%83%B3