<s>
The	O
International	O
Obfuscated	O
C	B-Language
Code	O
Contest	O
(	O
abbreviated	O
IOCCC	O
)	O
is	O
a	O
computer	B-General_Concept
programming	I-General_Concept
contest	O
for	O
the	O
most	O
creatively	O
obfuscated	O
C	B-Language
code	O
.	O
</s>
<s>
Held	O
annually	O
,	O
it	O
is	O
described	O
as	O
"	O
celebrating	O
 [ C's ] 	O
syntactical	O
opaqueness	O
"	O
.	O
</s>
<s>
Winning	O
entries	O
are	O
awarded	O
with	O
a	O
category	O
,	O
such	O
as	O
"	O
Worst	O
Abuse	O
of	O
the	O
C	B-Language
preprocessor	I-Language
"	O
or	O
"	O
Most	O
Erratic	O
Behavior	O
"	O
,	O
and	O
then	O
announced	O
on	O
the	O
official	O
IOCCC	O
website	O
.	O
</s>
<s>
The	O
idea	O
for	O
the	O
contest	O
came	O
after	O
they	O
compared	O
notes	O
with	O
each	O
other	O
about	O
some	O
poorly	O
written	O
code	O
that	O
they	O
had	O
to	O
fix	O
,	O
notably	O
the	B-Device
Bourne	I-Device
shell	I-Device
,	O
which	O
used	O
macros	O
to	O
emulate	O
ALGOL	B-Language
68	I-Language
syntax	O
,	O
and	O
a	O
buggy	O
version	O
of	O
finger	B-Application
for	O
BSD	O
.	O
</s>
<s>
Entries	O
often	O
employ	O
strange	O
or	O
unusual	O
tricks	O
,	O
such	O
as	O
using	O
the	O
C	B-Language
preprocessor	I-Language
to	O
do	O
things	O
it	O
was	O
not	O
designed	O
to	O
do	O
(	O
in	O
some	O
cases	O
"	O
spectacularly	O
"	O
,	O
according	O
to	O
Dr.	O
Dobbs	O
,	O
with	O
one	O
entry	O
creating	O
an	O
11-bit	O
ALU	B-General_Concept
in	O
the	O
C	O
preprocessorxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx1	O
IOCCC	O
.	O
</s>
<s>
Retrieved	O
2013-04-08.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx1	O
)	O
,	O
or	O
avoiding	O
commonly	O
used	O
constructs	O
in	O
the	O
C	B-Language
programming	I-Language
language	I-Language
in	O
favor	O
of	O
much	O
more	O
obscure	O
ways	O
of	O
achieving	O
the	O
same	O
thing	O
.	O
</s>
<s>
Contributions	O
have	O
included	O
source	O
code	O
formatted	O
to	O
resemble	O
images	O
,	O
text	O
,	O
etc.	O
,	O
after	O
the	O
manner	O
of	O
ASCII	O
art	O
,	O
preprocessor	O
redefinitions	O
to	O
make	O
code	O
harder	O
to	O
read	O
,	O
and	O
self-modifying	B-Application
code	I-Application
.	O
</s>
<s>
In	O
the	O
effort	O
to	O
take	O
obfuscation	O
to	O
its	O
extremes	O
,	O
contestants	O
have	O
produced	O
programs	O
which	O
skirt	O
around	O
the	O
edges	O
of	O
C	B-Language
standards	O
,	O
or	O
result	O
in	O
constructs	O
which	O
trigger	O
rarely	O
used	O
code	O
path	O
combinations	O
in	O
compilers	O
.	O
</s>
<s>
Toledo	O
NanochessToledo	O
Nanochess	O
is	O
a	O
chess	B-Application
engine	I-Application
created	O
by	O
Mexican	O
software	O
developer	O
Oscar	O
Toledo	O
Gutiérrez	O
,	O
a	O
five-time	O
winner	O
of	O
the	O
IOCCC	O
.	O
</s>
<s>
The	O
author	O
claims	O
that	O
it	O
is	O
the	O
world	O
's	O
smallest	O
chess	B-Application
program	I-Application
written	O
in	O
C	B-Language
.	O
</s>
<s>
The	O
source	O
code	O
for	O
Toledo	B-Application
Nanochess	I-Application
and	O
other	O
engines	O
is	O
available	O
.	O
</s>
<s>
Because	O
Toledo	B-Application
Nanochess	I-Application
is	O
based	O
on	O
Toledo	O
's	O
winning	O
entry	O
from	O
the	O
18th	O
IOCCC	O
(	O
Best	O
Game	O
)	O
,	O
it	O
is	O
heavily	O
obfuscated	O
.	O
</s>
<s>
On	O
February	O
2	O
,	O
2014	O
,	O
the	O
author	O
published	O
the	O
book	O
Toledo	B-Application
Nanochess	I-Application
:	O
The	O
commented	O
source	O
code	O
,	O
which	O
contains	O
the	O
fully	O
commented	O
source	O
code	O
.	O
</s>
<s>
As	O
of	O
February	O
7	O
,	O
2010	O
,	O
it	O
appears	O
to	O
be	O
one	O
of	O
only	O
two	O
chess	B-Application
engines	I-Application
written	O
in	O
less	O
than	O
2	O
kilobytes	O
of	O
C	B-Language
that	O
are	O
able	O
to	O
play	O
full	O
legal	O
chess	O
moves	O
,	O
along	O
with	O
Micro-Max	O
by	O
Dutch	O
physicist	O
H	O
.	O
G	O
.	O
Muller	O
.	O
</s>
<s>
*	O
g	O
=	O
9^	O
y:0	O
;}	O
_	O
L>N	O
)	O
{*	O
G	O
=O	O
_	O
s>1	O
)	O
{_	O
h&&	O
c-L	O
<	O
0	O
)	O
P	O
L	O
_	O
!	O
h	O
)	O
i	O
=	O
n	O
,	O
B	O
=O	O
,	O
b	O
=p	O
;}	O
N	O
=	O
L	O
;}	O
</s>
<s>
Below	O
is	O
a	O
1988	O
entry	O
which	O
calculates	O
pi	O
by	O
looking	O
at	O
its	O
own	O
area	O
:	O
"	O
westley.c	O
"	O
,	O
5th	O
International	O
Obfuscated	O
C	B-Language
Code	O
Contest	O
1988	O
)	O
.	O
</s>
