Hi, I discovered some macro Metafun particular. I then wanted to outline, but it does not fit with the boundary of the quadrant. Can I have some explanation ? Best regards, Fabrice \starttext \startMPcode u:=1cm ; pickup pencircle scaled 1pt ; fill ulcircle scaled 8u withcolor lightgray ; fill llcircle scaled 2u shifted (1u,0) withcolor lightgray ; fill lrcircle scaled 4u shifted (1u,1u) withcolor lightgray ; fill urcircle scaled 6u shifted (0,1u) withcolor lightgray ; label.lft(btex $x$ etex, (0,0.5u)) ; fill unitsquare scaled 1u withcolor lightgray ; draw unitsquare scaled 1u ; draw (-4u,0)--(0,0) dashed evenly ; draw (0,1u)--(0,4u) dashed evenly ; draw (1u,1u)--(3u,1u) dashed evenly ; draw (1u,0)--(1u,-1u) dashed evenly ; draw (-4u,0){up}..(0,4u)..(3u,1u){down} ; \stopMPcode \stoptext