Generate large dataset for a line chart

I need to test graphing application on a big data set. Data is in json format with the structure:

{
 "linechart":[
  {
   "x":[5,15,20,3],
   "y":[10,20,30,40]
  }
 ]
}

4 numbers represents 1 line, i.e. x[i] and y[i] is start point, while x[i+1] and y[i+1] is end point.

I want a chart to be inseparable (i.e. without "gaps"). By "big data set" i mean json of ~50mb as a perfect case, though it's not critical, the goal is to have at least a few thousand of points.

It is not possible to produce it manually and I can't think of any solution to this.