} def

/xlineto {
   /y2 exch def
   /x2 exch def
   /y1 exch def
   /x1 exch def
   0.1 setlinewidth White
   x1 y1 moveto x2 y2 lineto stroke
   0.04 setlinewidth Red
   x1 y1 moveto x2 y2 lineto stroke
} def

/circles {
  0 1 N 1 sub {
    /xloc exch def

    0 1 N 1 sub {
      /yloc exch def
      xloc yloc 0.09 0 360 arc fill
    } for
  } for
} def

/grid {
  0 1 N {
    /xloc exch def
   -0.5 xloc add -0.5 moveto
   -0.5 xloc add N .5 sub lineto
   stroke
  } for

  0 1 N {
    /yloc exch def
   -0.5 -0.5 yloc add moveto
    N .5 sub -0.5 yloc add lineto
   stroke
  } for
} def

150 200 translate
60 60 scale

0.02 setlinewidth
PineGreen grid
0.01 setlinewidth
Black moves
0.04 setlinewidth
Red path
Black circles
showpage