<s>
Polygons	B-General_Concept
are	O
used	O
in	O
computer	O
graphics	O
to	O
compose	O
images	O
that	O
are	O
three-dimensional	O
in	O
appearance	O
.	O
</s>
<s>
Usually	O
(	O
but	O
not	O
always	O
)	O
triangular	O
,	O
polygons	B-General_Concept
arise	O
when	O
an	O
object	O
's	O
surface	O
is	O
modeled	O
,	O
vertices	O
are	O
selected	O
,	O
and	O
the	O
object	O
is	O
rendered	O
in	O
a	O
wire	B-Algorithm
frame	I-Algorithm
model	I-Algorithm
.	O
</s>
<s>
This	O
is	O
quicker	O
to	O
display	O
than	O
a	O
shaded	O
model	O
;	O
thus	O
the	O
polygons	B-General_Concept
are	O
a	O
stage	O
in	O
computer	O
animation	O
.	O
</s>
<s>
The	O
polygon	B-General_Concept
count	I-General_Concept
refers	O
to	O
the	O
number	O
of	O
polygons	B-General_Concept
being	O
rendered	O
per	O
frame	O
.	O
</s>
<s>
Beginning	O
with	O
the	O
fifth	B-Application
generation	I-Application
of	I-Application
video	I-Application
game	I-Application
consoles	I-Application
,	O
the	O
use	O
of	O
polygons	B-General_Concept
became	O
more	O
common	O
,	O
and	O
with	O
each	O
succeeding	O
generation	O
,	O
polygonal	O
models	O
became	O
increasingly	O
complex	O
.	O
</s>
<s>
because	O
of	O
rounding	B-Algorithm
,	O
every	O
scanline	B-Algorithm
has	O
its	O
own	O
direction	O
in	O
space	O
and	O
may	O
show	O
its	O
front	O
or	O
back	O
side	O
to	O
the	O
viewer	O
.	O
</s>
