Emerald
15 000 XP
Has a chance to trigger once a day on a difficult ddk problem.
Uncommon
Recently completed by
Patrick Rogers 4k, 
Matthew Thiessen 10k, 
Tygo den Otter 9k, 
Phetlada Khamphira 14k, 
Simon Fadda 7k, 
WASAR WASAR (WASAR) 7k, 
Aidan Carlson 8k, 
ming! 10k
and 397 others.