Evan attended Matthew's Exhibition.
Music is an important element of Matthew's identity. Matthew sat down at the piano and played a pleasant piece in the beginning that he had composed in A minor. He explained about the piece, how it was a waltz, its key signature, and note lengths.
Then he talked in a lot of detail about music theory and some approaches to composition. For example, here is Matthew on arpeggios: Arpeggios are like chords, but they’re broken up into one note at time. (In an A minor chord, you play A, C, and E at the same time. In an arpeggio, you would play A, then C, the E, then high A, and then go back down.)
He let us go for a while and let us mess around on the instruments, trying to compose something. Then he brought us together to share our music with each other. At the end he played the piece that he played in the beginning again.
Here is a link to the sheet music of Matthew's composition in A minor.