autocrop
-1 6 setyrange
-6 7 setxrange
25 setxunit
/xA 5 def
/xB 4 def
/xC 3 def
/xD 2 def

/A {xA 0} def
/A' {xA neg 0} def
/B {xB 1} def
/B' {xB neg 1} def
/C {xC 2} def
/C' {xC neg 2} def
/D {xD 3} def
/D' {xD neg 3} def

.3 setlinewidth
[B B'] ligne
[C C'] ligne
[D D'] ligne

1 setlinewidth
/fillstyle {.4 setgray fill} def
[-1.5 0 {45 dir} .. 0 .3 {right} .. {-45 dir} 1.5 0] draw*
[-1.25 1 {45 dir} .. 0 1.3 {right} .. {-45 dir} 1.25 1] draw*
[-1 2 {45 dir} .. 0 2.3 {right} .. {-45 dir} 1 2] draw*
[-.8 3 {45 dir} .. 0 3.2 {right} .. {-45 dir} .8 3] draw*

[A B C D A' B' C' D'] {dupp 0 1 addv} papply {(-) line} dapply
[A B C] {0 1 addv dupp -1 0 addv} papply {(-) line} dapply
[A' B' C'] {0 1 addv dupp 1 0 addv} papply {(-) line} dapply
[A A'] ligne


setTimes
   (Sucre) 0 3.75 cctext
   (Fond) 0 -.5 cctext

.3 setlinewidth
.2 .5 stranslate
   [B C D] {dupp .75 0 addv} papply {(->) line} dapply
.8 0 stranslate
   (tamis 3) B crtext
   (tamis 2) C crtext
   (tamis 1) D crtext