z:
0
0

c:
1 0
0 1

P0:z-c
0 0
0 1

P1:z-c
0 1
1 1

P2:z-c
1 1
1 0

P3:z-c
1 0
0 0

T0:c-c
1 0.667
0 0.333

T1:c-c
0.333 0
0.667 1