1-4 - change the Oscillator type (sine, triangle, square, sawtooth)
A-L - play a major scale
W, E, T, Y, I - sharp notes
Z, C, B - increase the root note by 1, 10 or 20 Hz
X, V, N - decrease the root note by 1, 10 or 20 Hz
Q - restore the default frequency for the root - 440 Hz, or the piano note A4