% --- start of displayed preamble in the book --- input expressg % --- end of displayed preamble in the book --- defaultfont:="ptmr8r"; warningcheck:=0; beginfig(1) z1c=(0,0); drawLEVENT(1, 2cm, 1cm)(btex An event etex); z2c=(0,-1.5cm); drawdiamondbox(2, 3cm, 1cm) (btex questions? etex); z3=(0,-3cm); drawovalbox(3, 2cm, 1cm)(btex Oval etex); z4c=z3+(3cm,0); drawcirclebox(4, 2cm)(btex The End etex); drawarrow z1bm--z2tm; drawarrow z2bm--z3tm; drawarrow z3mr--z4ml; label.llft(btex No etex,z2bm); label.urt(btex Yes etex,z2mr); endfig; end;