%quadrillage
%marks
-4 4 setxrange
-1 5.5 setyrange
autocrop
30 setxunit
/r 3 def
/cerc {O r} def
0 cerc cpoint /B defpoint
180 cerc cpoint /A defpoint
110 cerc cpoint /E defpoint

O E E perp /tgte_E defdroite
O A A perp /tgte_A defdroite
O B B perp /tgte_B defdroite
tgte_A tgte_E interdroite /I defpoint
tgte_B tgte_E interdroite /J defpoint
I A 1.2 hompoint /I' defpoint
J B 1.2 hompoint /J' defpoint

%[A B O I J E I' J'] {times2} plot

1 setlinewidth
0 180 cerc Cercle

.8 setlinewidth
tgte_E droite
[I' A B J'] ligne
[O E] ligne

.6 setlinewidth

I A O angledroit
J E O angledroit
O B J angledroit

gsave
   pointilles
   [I O J] ligne
grestore

setTimesItalic
   (O) O dctext
   (A) A dltext
   (B) B drtext
   (I) I ultext
   (J) J urtext
   (E) E ultext

10 setfontsize
setTimesItalic
I O A .5 (-) tripointarc
(x) 165 O .7 cpoint cctext
E O I .7 (-) tripointarc
(x) 130 O .9 cpoint cctext
J O E .5 (=) tripointarc
(y) 80 O .7 cpoint cctext
B O J .7 (=) tripointarc
(y) 25 O .9 cpoint cctext

O I E .5 (=) tripointarc
(y) 0 I .7 cpoint cctext
A I O .4 (=) tripointarc
(y) -70 I .6 cpoint cctext
O J B .5 (-) tripointarc
(x) -105 J .7 cpoint cctext
E J O .7 (-) tripointarc
(x) -140 J .9 cpoint cctext

E O 1 marked
A O 1 marked