%prologues:=3; % This is needed to produce eps
outputtemplate := "%j-%c.svg"; % To produce svg instead of eps
outputformat := "svg"; % To produce svg instead of eps

chasse := 250;
hauteur := 500;

deviate := uniformdeviate 90 - 45;

rright := 0 + deviate;
rup := 90 + deviate;
rleft := 180 + deviate;
rdown := 270 + deviate;

beginfig(128);
x1 := 0;
x3 := chasse;
x2 = .5[x1, x3];
x4 = .5[x1, x3];

y4 := 0;
y2 = hauteur;
y1 = .5[y4, y2];
y3 = .5[y4, y2];

fill (0 - 100, 0 - 100)--(0 - 100, hauteur + 100)--(chasse + 100, hauteur + 100)--(chasse + 100, 0 - 100)--cycle withcolor white;

pickup pencircle scaled 20;
draw z1..z2..z3..z4..cycle;
pickup pencircle scaled 24;
draw z1..z2..{dir rdown}z3..z4..cycle  withcolor white;
pickup pencircle scaled 20;
draw z1..z2..{dir rdown}z3..z4..cycle  withcolor blue;
deviate := uniformdeviate 90 - 45;
rdown := 270 + deviate;
pickup pencircle scaled 24;
draw z1..z2..{dir rdown}z3..z4..cycle  withcolor white;
pickup pencircle scaled 20;
draw z1..z2..{dir rdown}z3..z4..cycle  withcolor red;

for i=1 upto 4:
dotlabels.bot([i]);
endfor;

endfig;

end;