<s>
Polyworld	B-Application
is	O
a	O
cross-platform	O
(	O
Linux	B-Application
,	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
)	O
program	O
written	O
by	O
Larry	O
Yaeger	O
to	O
evolve	O
Artificial	B-Application
Intelligence	I-Application
through	O
natural	B-Application
selection	I-Application
and	O
evolutionary	B-Algorithm
algorithms	I-Algorithm
.	O
</s>
<s>
It	O
uses	O
the	O
Qt	B-Language
graphics	O
toolkit	O
and	O
OpenGL	B-Application
to	O
display	O
a	O
graphical	O
environment	O
in	O
which	O
a	O
population	O
of	O
trapezoid	O
agents	O
search	O
for	O
food	O
,	O
mate	O
,	O
have	O
offspring	O
,	O
and	O
prey	O
on	O
each	O
other	O
.	O
</s>
<s>
Each	O
individual	O
makes	O
decisions	O
based	O
on	O
a	O
neural	B-Architecture
net	I-Architecture
using	O
Hebbian	O
learning	O
;	O
the	O
neural	B-Architecture
net	I-Architecture
is	O
derived	O
from	O
each	O
individual	O
's	O
genome	O
.	O
</s>
<s>
The	O
genome	O
does	O
not	O
merely	O
specify	O
the	O
wiring	O
of	O
the	O
neural	B-Architecture
nets	I-Architecture
,	O
but	O
also	O
determines	O
their	O
size	O
,	O
speed	O
,	O
color	O
,	O
mutation	O
rate	O
and	O
a	O
number	O
of	O
other	O
factors	O
.	O
</s>
