code: func GenerateGrid(nodes int, spacing time.Duration) [][]time.Duration {
  	truth := make([][]time.Duration, nodes)
  	for i := range truth {
  		truth[i] = make([]time.Duration, nodes)
  	}
  
  	n := int(math.Sqrt(float64(nodes)))
  	for i := 0; i < nodes; i++ {
  		for j := i + 1; j < nodes; j++ {
  			x1, y1 := float64(i%n), float64(i/n)
  			x2, y2 := float64(j%n), float64(j/n)
  			dx, dy := x2-x1, y2-y1
  			dist := math.Sqrt(dx*dx + dy*dy)
  			rtt := time.Duration(dist * float64(spacing))
  			truth[i][j], truth[j][i] = rtt, rtt
  		}
  	}
  	return truth
  }
docs: // GenerateGrid returns a truth matrix as if all the nodes are in a two dimensional
  // grid with the given spacing between them.