We have applied the short cell reduction along the first cell of length 3 of this spine:

2 = { 5, 6 }
3 = { 8 }
Cell #11 = { -#17 }
Cell #12 = { #16, #17, -#16, 5, 8, -5, #13, #17, -#13, -6, -8, 6, #16, -#13 }

You can also view the graph code:

Graph code :
	5	V2	V4
	6	V4	V2
	8	V4	V4
	#13	V2	V#8
	#16	V2	V#8
	#17	V#8	V#8