code: function(g, coords) {
          if (!coords || !coords.length)
              return;
          g.moveTo(coords[0][0], coords[0][1]);
          for (var i = 1; i < coords.length; i++) {
              g.lineTo(coords[i][0], coords[i][1]);
          }
      }
docs: ----------------------------------------------------------------------- Private methods 
  Trace the specified path on the given canvas context.
  
  @param g
  canvas context
  @param coords
  a sequence of coordinates to trace