| Incidence matrix of Figure 8 | P-invariant | |||||||||||||
|
| T1 | T2 | T3 | T4 | T5 | T6 | T7 | T8 | T9 | T10 | T11 |
|
|
|
| P1 | −1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | P1 |
| 1 |
| P2 | 1 | −1 | −1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | P2 | −1 | 0 |
| P3 | −1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | P3 | −1 | 0 |
| P4 | 0 | −1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | P4 |
| 0 |
| P5 | 0 | 1 | 0 | −1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | P5 |
| 0 |
| P6 | 0 | 0 | 1 | 0 | −1 | 0 | 0 | 0 | 0 | 0 | 0 | P6 |
| 1 |
| P7 | 0 | 0 | 0 | 0 | 1 | −1 | 0 | 0 | 0 | 0 | 0 | P7 |
| 1 |
| P8 | 0 | 0 | 0 | 0 | 0 | 1 | −1 | 0 | 0 | 0 | 0 | P8 | 1 | 0 |
| P9 | 0 | 0 | −1 | 0 | 1 | 0 | 0 | 0 | 0 | −1 | 1 | P9 | 0 | 1 |
| P10 | 0 | 0 | 0 | 0 | −1 | 1 | 0 | 0 | −1 | 1 | 0 | P10 | 1 | 1 |
| P11 | 0 | 0 | 0 | 0 | 0 | −1 | 1 | −1 | 1 | 0 | 0 | P11 | 1 | −1 |
| P12 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | −1 | 0 | 0 | P12 |
| −1 |
| P13 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | −1 | 0 | P13 | 1 | 0 |
| P14 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | −1 | P14 |
| 1 |
| P15 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | −1 | 0 | 0 | 1 | P15 | 0 | 0 |
| VS1 | 0 | 0 | 0 | 0 | −1 | 1 | 0 | −1 | 1 | 0 | 0 | VS1 | −1 | −1 |
| VS2 | −1 | 0 | −1 | 1 | 1 | 0 | 0 | −1 | 0 | 1 | 0 | VS2 |
| −1 |