Emerald
15 000 XP
Has a chance to trigger once a day on a difficult ddk problem.
Uncommon
Recently completed by
Tygo den Otter 9k, 
Phetlada Khamphira 14k, 
Simon Fadda 7k, 
WASAR WASAR (WASAR) 7k, 
Aidan Carlson 8k, 
ming! 10k,
and 395 others.