When you copy an exterior line, the new line is located halfway between the line you copied and the nearest line parallel to the line you copied.
1	When	when	SCONJ	_	Case=Nom	3	mark	_	_
2	you	you	PRON	PERS-P2	_	3	nsubj	_	_
3	copy	copy	VERB	PRES	Mood=Ind|Tense=Pres|VerbForm=Fin	12	advcl	_	_
4	an	an	DET	IND-SG	Definite=Ind|PronType=Art	6	det	_	_
5	exterior	exterior	ADJ	POS	Degree=Pos	6	amod	_	_
6	line	line	NOUN	SG-NOM	Number=Sing	3	obj	_	SpaceAfter=No
7	,	,	PUNCT	Comma	_	3	punct	_	_
8	the	the	DET	DEF	Definite=Def|PronType=Art	10	det	_	_
9	new	new	ADJ	POS	Degree=Pos	10	amod	_	_
10	line	line	NOUN	SG-NOM	Number=Sing	12	nsubj:pass	_	_
11	is	be	AUX	PRES-AUX	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	12	aux:pass	_	_
12	located	locate	VERB	PASS	Tense=Past|VerbForm=Part|Voice=Pass	0	root	_	_
13	halfway	halfway	ADV	_	_	16	advmod	_	_
14	between	between	ADP	_	_	16	case	_	_
15	the	the	DET	DEF	Definite=Def|PronType=Art	16	det	_	_
16	line	line	NOUN	SG-NOM	Number=Sing	12	obl	_	_
17	you	you	PRON	PERS-P2	_	18	nsubj	_	_
18	copied	copy	VERB	PAST	Tense=Past|VerbForm=Part	16	acl:relcl	_	_
19	and	and	CCONJ	_	_	22	cc	_	_
20	the	the	DET	DEF	Definite=Def|PronType=Art	22	det	_	_
21	nearest	near	ADJ	SPL	Degree=Sup	22	amod	_	_
22	line	line	NOUN	SG-NOM	Number=Sing	16	conj	_	_
23	parallel	parallel	ADJ	POS	Degree=Pos	22	amod	_	_
24	to	to	ADP	_	_	26	case	_	_
25	the	the	DET	DEF	Definite=Def|PronType=Art	26	det	_	_
26	line	line	NOUN	SG-NOM	Number=Sing	23	nmod	_	_
27	you	you	PRON	PERS-P2	_	28	nsubj	_	_
28	copied	copy	VERB	PAST	Tense=Past|VerbForm=Part	26	acl:relcl	_	SpaceAfter=No
29	.	.	PUNCT	Period	_	12	punct	_	_
