% --- start of displayed preamble in the book ---
input metafun
% --- end of displayed preamble in the book ---
defaultfont:="ptmr8r";
warningcheck:=0;
beginfig(1)
draw simplified
(((0,0)--(1,0)--(2,0)--
(2,1)--(0,1)--cycle)
scaled 1.5cm);
endfig;
end;
