%Section d'une pyramide créee dans un cube

input geometriesyr16;
u:=0.5cm;
figure(0,0,11u,11u);
z0=(1*u,1*u);label.llft(btex $A$ etex,z0);
z1=z0 shifted (6*u,0);label.lrt(btex $B$ etex,z1);
z3=z0 shifted (3*u,2*u);label.lft(btex $D$ etex,z3);
z4=z0 shifted (0,6*u);label.ulft(btex $E$ etex,z4);
z5=z4 shifted (6*u,0);label.top(btex $F$ etex,z5);
z2=z1 shifted (3*u,2*u);label.rt(btex $C$ etex,z2);
z6=z5 shifted (3*u,2*u);label.urt(btex $G$ etex,z6);
z7=z4 shifted (3*u,2*u);label.top(btex $H$ etex,z7);
draw z0--z1--z2--z6--z7--z4--cycle;
draw z4--z5--z6;draw z5--z1--z6;
draw z7--z3--z0 dashed evenly;
draw z6--z3--z1 dashed evenly;
draw z2--z3 dashed evenly;
z8=3/5[z6,z2];label.rt(btex $J$ etex,z8);
z9=3/5[z6,z1];label.lrt(btex $K$ etex,z9);
z10=3/5[z6,z3];label.ulft(btex $L$ etex,z10);
draw z8--z9;
draw z8--z10--z9 dashed evenly;
fin;
end