(a:Vector2, b:Vector2)
return a.x * b.y - a.y * b.x
scalar value; tells direction of rotation from a to b; 
    see direction_of_bend()
    # See http://www.allenchou.net/2013/07/cross-product-of-2d-vectors/
scalar value; tells direction of rotation from a to b; 
    see direction_of_bend()
    # See http://www.allenchou.net/2013/07/cross-product-of-2d-vectors/
scalar value ; tells direction of rotation from a to b ; see direction_of_bend () # See http : // www . allenchou . net / 2013 / 07 / cross - product - of - 2d - vectors /
def cross_2d(a:Vector2, b:Vector2) -> float:
    """
    scalar value; tells direction of rotation from a to b; 
    see direction_of_bend()
    # See http://www.allenchou.net/2013/07/cross-product-of-2d-vectors/
    """
    return a.x * b.y - a.y * b.x
def cross_2d ( a : Vector2 , b : Vector2 ) -> float : return a . x * b . y - a . y * b . x