That, I think, started my thinking about this, but it took a while for the idea to crystallize.
1	That	that	PRON	DT	Number=Sing|PronType=Dem	6	nsubj	6:nsubj	Discourse=elaboration-additional:20->12:3|Entity=(31-event-giv:act-cf2-1-coref)|SpaceAfter=No
2	,	,	PUNCT	,	_	1	punct	1:punct	_
3	I	I	PRON	PRP	Case=Nom|Number=Sing|Person=1|PronType=Prs	4	nsubj	4:nsubj	Discourse=attribution-positive:21->22:0|Entity=(2-person-giv:act-cf1*-1-ana)
4	think	think	VERB	VBP	Mood=Ind|Number=Sing|Person=1|Tense=Pres|VerbForm=Fin	6	advcl	6:advcl	SpaceAfter=No
5	,	,	PUNCT	,	_	4	punct	4:punct	_
6	started	start	VERB	VBD	Mood=Ind|Number=Sing|Person=3|Tense=Past|VerbForm=Fin	0	root	0:root	Discourse=same-unit_m:22->20:0
7	my	my	PRON	PRP$	Case=Gen|Number=Sing|Person=1|Poss=Yes|PronType=Prs	8	nmod:poss	8:nmod:poss	Entity=(34-event-new-cf5-2-sgl(2-person-giv:act-cf1*-1-ana)
8	thinking	thinking	NOUN	NN	Number=Sing	6	obj	6:obj	_
9	about	about	ADP	IN	_	10	case	10:case	_
10	this	this	PRON	DT	Number=Sing|PronType=Dem	8	nmod	8:nmod:about	Entity=(13-event-giv:inact-cf3-1-ana)34)|SpaceAfter=No
11	,	,	PUNCT	,	_	14	punct	14:punct	_
12	but	but	CCONJ	CC	_	14	cc	14:cc	Discourse=adversative-concession:23->20:1
13	it	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	14	expl	14:expl	Entity=(35-event-new-cf4-1-cata)
14	took	take	VERB	VBD	Mood=Ind|Number=Sing|Person=3|Tense=Past|VerbForm=Fin	6	conj	6:conj:but	_
15	a	a	DET	DT	Definite=Ind|PronType=Art	16	det	16:det	Entity=(36-time-new-cf6-2-sgl
16	while	while	NOUN	NN	Number=Sing	14	obj	14:obj	Entity=36)
17	for	for	ADP	IN	_	19	case	19:case	Entity=(35-event-acc:com-cf4-5-coref
18	the	the	DET	DT	Definite=Def|PronType=Art	19	det	19:det	Entity=(37-abstract-new-cf7-2-sgl
19	idea	idea	NOUN	NN	Number=Sing	16	nmod	16:nmod:for	Entity=37)
20	to	to	PART	TO	_	21	mark	21:mark	_
21	crystallize	crystallize	VERB	VB	VerbForm=Inf	14	csubj	14:csubj	Entity=35)|SpaceAfter=No
22	.	.	PUNCT	.	_	6	punct	6:punct	_
