void increase_tempo(uint8_t tempo_change);
void decrease_tempo(uint8_t tempo_change);
+#define SCALE (int []){ 0 + (12*0), 2 + (12*0), 4 + (12*0), 5 + (12*0), 7 + (12*0), 9 + (12*0), 11 + (12*0), \
+ 0 + (12*1), 2 + (12*1), 4 + (12*1), 5 + (12*1), 7 + (12*1), 9 + (12*1), 11 + (12*1), \
+ 0 + (12*2), 2 + (12*2), 4 + (12*2), 5 + (12*2), 7 + (12*2), 9 + (12*2), 11 + (12*2), \
+ 0 + (12*3), 2 + (12*3), 4 + (12*3), 5 + (12*3), 7 + (12*3), 9 + (12*3), 11 + (12*3), \
+ 0 + (12*4), 2 + (12*4), 4 + (12*4), 5 + (12*4), 7 + (12*4), 9 + (12*4), 11 + (12*4), }
+
// These macros are used to allow play_notes to play an array of indeterminate
// length. This works around the limitation of C's sizeof operation on pointers.
// The global float array for the song must be used here.