Stop show with sound  Next slide in show -- Keyboard shortcut: 'n'  27 secondsLecture 3 - slide 21 : 42
Program 2
1> (number-interval 1 10)
(1 2 3 4 5 6 7 8 9 10)

2> (number-interval-iter 10 20)
(10 11 12 13 14 15 16 17 18 19 20)

3> (number-interval-iter 20 10)
()