% --- start of displayed preamble in the book --- input hatching; % --- end of displayed preamble in the book --- % graphic converted to gray in book using 'color2gray' defaultfont:="ptmr8r"; warningcheck:=0; beginfig(1) path p; p:=unitsquare xscaled 30mm yscaled 15mm; hatchfill p withcolor red withcolor (45,2mm,-.5bp) withcolor (-45,2mm,-.5bp); endfig; end;