 \vec{ a } 

 \vec{ a } 

 \vec{ b } 

 \vec{ b } 

  \vec{ c } 

 \vec{ a } +  \vec{ b }  

 \vec{ b }+ \vec{ a }  

 \vec{ b } + \vec{ c } 

A = (-1, 1)
B = (1, 5)
u = Vector(A, B)
E = (3, 0)
v = Vector(A, E)
c: u + v
C = Point(c)
a = Segment(B, C)
D = (7, 1)
w = Vector(C, D)
z = Vector(B, C)
b = Vector(E, C)
d = Vector(A, D)
e = Vector(B, D)