There are groups which express the symmetry of some structures.
1	There	there	PRON	EX	PronType=Dem	2	expl	2:expl	Discourse=elaboration-additional:14->12:1
2	are	be	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	0:root	_
3	groups	group	NOUN	NNS	Number=Plur	2	nsubj	2:nsubj|5:nsubj	Entity=(24-abstract-new-cf1-1-sgl
4	which	which	PRON	WDT	PronType=Rel	5	nsubj	3:ref	Discourse=elaboration-attribute:15->14:0
5	express	express	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	3	acl:relcl	3:acl:relcl	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	7:det	Entity=(25-abstract-new-cf2-2-sgl
7	symmetry	symmetry	NOUN	NN	Number=Sing	5	obj	5:obj	_
8	of	of	ADP	IN	_	10	case	10:case	_
9	some	some	DET	DT	PronType=Ind	10	det	10:det	Entity=(26-abstract-new-cf3-2-sgl
10	structures	structure	NOUN	NNS	Number=Plur	7	nmod	7:nmod:of	Entity=26)25)24)|SpaceAfter=No
11	.	.	PUNCT	.	_	2	punct	2:punct	_
