[CM] negative number in cond

[bil at ccrma.Stanford.EDU]

By the way, you can use s7's lint to find problems
like this.  If I run your code through lint, among
other things it prints out:

...
ruby4 (line 56): perhaps (and (>= -6 theslope) (<= theslope -10)) -> (<= 
theslope -10)
...

and finally (after complaining about dead code in cond):

ruby4 (line 83): perhaps
     (cond ((and (>= theslope -5) (<= theslope -1)) (begin (print "chose 
case... ->
     (cond ((>= -1 theslope -5) (begin (print "chose case 0") (set! 
thecase 0)))
           ((<= theslope -10) (begin (print "chose case 1") (set! thecase 
1))))