% --- start of displayed preamble in the book --- input boxes % --- end of displayed preamble in the book --- defaultfont:="ptmr8r"; warningcheck:=0; beginfig(1) boxjoin(a.e=b.w-(30,0)); boxit.one("One"); circleit.two("Two"); drawboxed(one,two); label.lft("1.",one.w); label.rt("2.",two.e); label.top("a.", point .5*length (one.c{dir 45}..two.c) of (one.c{dir 45}..two.c) ); draw one.c{dir 45}..two.c cutbefore bpath one cutafter bpath two; endfig; end;