Noir ou blanc
Les disques aux intersections des allées grises sont-ils noirs ou blancs?
u = 25;
path carre;
carre = ((-1,-1) -- (-1,1) -- (1,1) -- (1,-1) -- cycle)
scaled (u-5);
picture grille;
path cadre;
beginfig(1);
grille = image (
for j:=1 upto 9:
for h:=1 upto 6:
fill carre shifted (2*j*u,2*h*u)
withcolor black;
endfor;
endfor;
);
cadre = bbox(grille);
fill cadre withcolor .5white;
draw grille;
for j:=1 upto 8:
for h:=1 upto 5:
fill fullcircle scaled 10 shifted ((2*j+1)*u,(2*h+1)*u)
withcolor white;
endfor;
endfor;
draw bbox(currentpicture) withcolor blue;
endfig;
end