P = transpose[(p1,p2,p3)]

Q = transpose[(q1,q2,q3)]

-p1+p2-p3 = 1

p2 - p3 = 1

-----------------

p1 = 0, p2 = 1+p3

~~~~~~~~~~~~~~~~~

-q1+q2-q3 = p2

q2 - q3 = p3

----------------

-q1 = p2-p3 = 1 --------> q1= -1

q2 = p3 + q3

P = transpose[(0, 1+p3, p3)]

Q = transpose[(-1, p3 + q3, q3)]

which means you've got 2 D.O.F's let's choose for instance q3 = p3 = 0

P = transpose[(0,1,0)] Q = transpose[(-1,0,0)]