title: How to do linepoints with filled points in gnuplot?
body: <p>I have another problem with gnuplot, maybe someone has a good idea, what to do:</p>
  
  <p>I wanted to plot some simple lines with points in black and white. Each line should get its own symbols for point but same style. Black border and white or grey on the inside, but then different shapes like circle or triangle.
  So far I am just able to produce the border, but inside is either completely empty/blank or I get just rounded interruptions. For my understanding this is due to the pi (pointinterval) command, but shape is always just a circle and not matching when using triangles.</p>
  
  <p>My used linestyle is</p>
  
  <pre><code>set style line 1 lt -1 lw 2 pi -4 pt 17 ps 1
  plot    f(x) w lp ls 1
  </code></pre>
  
  <p>So my questions is, how can I produce a line with points, which have a border with line color and a filled inside of any wished color?</p>
  
  <p>Thought this is not too difficult, but up for now I am full-blown stuck, so thank you for any advice!</p>