Of the three subtypes Sung from episode 15, one of them is so different from the others that it's called a "counter-type". It makes a 7 look like a 2 and a 4 look like a 3. In this episode, Sung makes Nate guess which of the three subtypes is the oddball. They go through every single number in the enneagram so you can find your subtype and try to do better than Nate, who got 8 out of 9 guesses correct.