-12.5 4.5 setxrange
-1 2.5 setyrange
50 setxunit
18 setfontsize

traceOx
axeOxarrow
/ticklength {10} def
xticks
0 xtick
%[-9 -4 1] {xmark} apply
/a {3} def
/b {-0.4} def
(1) 1 b [a dup] dctext
(0) 0 b [a dup] dctext
(-4) -4 b [a dup] dctext
(-9) -9 b [a dup] dctext
(5) -6.5 2.2 [a dup] cctext
(5) -1.5 2.2 [a dup] cctext

/arrowscale {2 dup} def
/angleA 130 def
/angleB 50 def
-4 0.5 -9 0.5 (->) pccurve


/angleA 50 def
/angleB 130 def
-4 0.5 1 0.5 (->) pccurve