2015-02-15 #ruby
2015-02-11 #ruby
2013-10-05 #ruby
2013-06-01 #ruby
2012-12-27 #ruby
2011-08-15 #ruby
2009-05-16 #ruby #math
2009-05-15 #ruby #math
2009-01-22 #ruby #c
2008-03-21 #ruby
2007-11-25 #ruby