% --- start of displayed preamble in the book --- input exteps % --- end of displayed preamble in the book --- % graphic converted to gray in book using 'color2gray' defaultfont:="ptmr8r"; warningcheck:=0; beginfig(1) begineps "gradient.eps"; base := (25,25); clipping:=true; grid:=true; epsdrawdot(10pct,40pct) withpen pencircle scaled 10pct withcolor blue; epsdrawdot(60pct,20pct) withpen pencircle scaled 10pct withcolor red; endeps; draw origin withpen pencircle scaled 30 withcolor blue+green; endfig; end;