% --- start of displayed preamble in the book ---

% --- start of displayed preamble in the book ---

% --- end of displayed preamble in the book ---
defaultfont:="ptmr8r";
warningcheck:=0;
beginfig(1)
draw fullcircle scaled 2cm;
picture savepic;
savepic=currentpicture;
currentpicture:=nullpicture;
draw savepic scaled .5;
draw savepic scaled .5 shifted (3cm,0);
endfig;
end;