%!
/SIZE 500 def
20 20 translate
0 0 moveto SIZE 0 rlineto 0 SIZE rlineto SIZE neg 0 rlineto 0 SIZE neg rlineto
.5 setlinewidth stroke 1.5 setlinewidth

/lineseg { SIZE mul exch SIZE mul exch moveto 
           SIZE mul exch SIZE mul exch lineto 
           stroke } def
/point { SIZE mul exch SIZE mul exch 2 0 369 arc fill } def

 0.00  0.12 0.23  1.00 lineseg
 1.00  0.41 0.00  0.52 lineseg
 1.00  0.20 0.30  1.00 lineseg
 0.00  0.40 0.10  0.00 lineseg
 1.00  0.35 0.10  1.00 lineseg
 
 0.25 0.8 point 0.6 0.5 point
 0.95 0.1 point 0.11 0.5 point

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