The first day of the second week, everyone looked tired even before the class started, probably because of excess entertainment on the weekend. Nevertheless, most of the students stayed interested in the lectures and activities. We talked about data compression and started out on an exercise with a case where the data is binary and 1's are sparse. Next, Mark invented his six-letter language and Jesse, Soon-young and Kim came up with the best compression scheme for that, and Mark rewarded each of them with prizes he bought from the National Air and Space Museum in Washington DC, which he visited over the weekend. The last activity was buidling Huffman trees for the English language in groups of two and compressing messages with the trees they came up with. Carolyn, Serhat, Ari and Sung-Ha completed the task the fastest, and they were all rewarded.