code: func (l *Line) Interpolate(percent float64) *Point {
  	return &Point{
  		l.a[0] + percent*(l.b[0]-l.a[0]),
  		l.a[1] + percent*(l.b[1]-l.a[1]),
  	}
  }
docs: // Interpolate performs a simple linear interpolation, from A to B.
  // This function is the opposite of Project.