title: Plot multiple sets of points in R
body: <p>I have multiple sets of xy pairs that I want to plot.  I want each set of xy pairs to be connected by a line.  In other words the goal is to have multiple experimental instances each approximated by a line plotted on one plot.  Also how would I colour the lines differently?</p>
  
  <p>The plot function does what I want, but takes on one set of xy pairs:
  <code>plot(x, y, ...)</code></p>
  
  <p>Can this function be made to take multiple sets or is there another function for that?</p>