code: func (ps PointSet) Bound() *Bound {
  	if len(ps) == 0 {
  		return NewBound(0, 0, 0, 0)
  	}
  
  	minX := math.Inf(1)
  	minY := math.Inf(1)
  
  	maxX := math.Inf(-1)
  	maxY := math.Inf(-1)
  
  	for _, v := range ps {
  		minX = math.Min(minX, v.X())
  		minY = math.Min(minY, v.Y())
  
  		maxX = math.Max(maxX, v.X())
  		maxY = math.Max(maxY, v.Y())
  	}
  
  	return NewBound(maxX, minX, maxY, minY)
  }
docs: // Bound returns a bound around the point set. Simply uses rectangular coordinates.