submission by jtoy
function meshgrid(xs,ys){
  new_xs =[]
  new_ys = []
  for(iy=0;iy<ys.length;iy++){
    xrow = []
    yrow = []
    for(ix=0;ix<xs.length;ix++){
      xrow.push(xs[ix])
      yrow.push(ys[iy])
    }

    new_xs.push(xrow)
    new_ys.push(yrow)
  }
  return [new_xs,new_ys]
}

function setup(){
  var myCanvas = createCanvas(windowWidth,windowHeight); //you must keep this line unmodified
    console.log(JSON.stringify(meshgrid([2,3,5],[1]) ))
   ellipse(0,0,40,40)

}