if ~exist('waterpipesDone') then
 display 'first execute waterpipes.pcm'
 return
endif
clear
window 1 0 0 80 100
defaults
set
 xnumberson 0
 ynumberson 0
 xticson 0
 yticson 0
 xcross 1
 ycross 1
 graphbox 0
 xaxison 0
 yaxison 0

scales\commensurate\-messages -15 100 -15 100
set curvecolor blue
graph [-10;90] [10;90]
a = 0.8
b = 18
v = 20
w = 80
set plotsymbol 17
set plotsymbolcolor green
graph\overlay v w
set curvecolor black
set plotsymbol 0
graph\overlay [v;v] [a*v+b;w]
graph\overlay [(w-b)/a;v] [w;w]
c = (1/a)*[w-b-(w-b-a*v)/(a*a+1)]
d = a*c+b
set curvecolor blue
graph\overlay [c;v] [d;w]
set
 textinteractive 0
 %textheight 5
 textalign 3
 %xtextlocation 42
 %ytextlocation 75

text '(x,y)'
set
 textalign 1
 %xtextlocation 53
 %ytextlocation 53

text '(v,w)'
set %xtextlocation 70
set %ytextlocation 71
text '((y-B)/A,y)'
set %xtextlocation 44
set %ytextlocation 42
text '(x,A*x+B)'
set
 %textheight 5
 %xtextlocation 50
 %ytextlocation 33

text 'v = (1/A)*[y-B-(y-B-A*x)/(A*A+1)]'
set %ytextlocation 27
text 'w = A*v+B'
!
b2 = a*46+b
b3 = 46/a+b2
b4 = (-1/a)*42+b3
b5 = -a*42+b4
x1 = (105-b5)/(a+1.25)
y1 = a*x1+b5
set curvecolor black
graph\overlay [46;42;x1] [b2;b4;y1]