Diagram

Order

1

${\epsilon }^{2}NCT$

2

${\epsilon }^{3}NCT$

3

${\epsilon }^{4}NCT$

4

${\epsilon }^{3}N{C}^{2}T$

5

${\epsilon }^{4}N{C}^{2}T$

6

${\left({\epsilon }^{2}NCT\right)}^2$