<s>
The	O
centrolinead	B-Application
was	O
invented	O
by	O
Peter	O
Nicholson	O
,	O
a	O
British	O
mathematician	O
and	O
architect	B-Application
,	O
in	O
1814	O
.	O
</s>
<s>
It	O
was	O
used	O
to	O
construct	O
2-point	O
perspective	B-Architecture
drawings	I-Architecture
where	O
one	O
or	O
both	O
vanishing	B-General_Concept
points	I-General_Concept
existed	O
outside	O
the	O
drawing	O
board	O
.	O
</s>
<s>
Draftsmen	B-Application
could	O
use	O
the	O
instrument	O
in	O
pairs	O
;	O
one	O
for	O
each	O
vanishing	B-General_Concept
point	I-General_Concept
on	O
each	O
side	O
of	O
the	O
station	O
point	O
.	O
</s>
<s>
Centrolineads	B-Application
were	O
produced	O
in	O
various	O
sizes	O
.	O
</s>
<s>
A	O
third	O
centrolinead	B-Application
could	O
be	O
used	O
to	O
construct	O
3-point	O
perspective	O
.	O
</s>
<s>
The	O
diagram	O
shown	O
above	O
does	O
not	O
represent	O
the	O
centrolinead	B-Application
designed	O
by	O
Nicholson	O
.	O
</s>
