[frankfrank13]

I guess, but the sequence of positions 6->5->4->3->2-1 maps to valves

- 1+3 (6)

- 2+3 (5)

- 1+2 (4)

- 1 (3)

- 2 (2)

- open (1)

All I mean to say, sliding a little bit at a time up the slide is easy to map to "short slide higher pitch" in a way that valves don't