func SameSideOfTriangle<N>(p0 Point2D<N>, p1 Point2D<N>, a Point2D<N>, b Point2D<N>) bool where N: Number {
        ba := Point2D(b.x.Sub(a.x), b.y.Sub(a.y))
        p0a := Point2D(p0.x.Sub(a.x), p0.y.Sub(a.y))
        p1a := Point2D(p1.x.Sub(a.x), p1.y.Sub(a.y))
        cp0 := ba.x.Mul(p0a.y).Sub(p0a.x.Mul(ba.y))
        cp1 := ba.x.Mul(p1a.y).Sub(p1a.x.Mul(ba.y))
        dot := cp0.x.Mul(cp1.x).Add(cp0.y.Mul(cp1.y))
        return dot >= 0
    }

    func SameSideOfTriangle<N>(p0 Point2D<N>, p1 Point2D<N>, a Point2D<N>, b Point2D<N>) bool where N: Number {
        ba := Point2D(b.x - a.x, b.y - a.y)
        p0a := Point2D(p0.x - a.x, p0.y - a.y)
        p1a := Point2D(p1.x - a.x, p1.y - a.y)
        cp0 := ba.x * p0a.y - p0a.x * ba.y
        cp1 := ba.x * p1a.y - p1a.x * ba.y
        dot := cp0.x * cp1.x + cp0.y * cp1.y
        return dot >= 0
    }