<s>
Zillions	B-Application
of	I-Application
Games	I-Application
is	O
a	O
commercial	O
general	B-Algorithm
game	I-Algorithm
playing	I-Algorithm
system	O
developed	O
by	O
Jeff	O
Mallett	O
and	O
Mark	O
Lefler	O
in	O
1998	O
.	O
</s>
<s>
The	O
game	O
rules	O
are	O
specified	O
with	O
S-expressions	B-Protocol
,	O
Zillions	O
rule	O
language	O
.	O
</s>
<s>
After	O
parsing	O
the	O
rules	O
of	O
the	O
game	O
,	O
the	O
system	O
's	O
artificial	B-Application
intelligence	I-Application
can	O
automatically	O
play	O
one	O
or	O
more	O
players	O
.	O
</s>
<s>
The	O
scripting	O
language	O
of	O
Zillions-of-Games	O
uses	O
S-expressions	B-Protocol
.	O
</s>
<s>
The	O
rules	O
are	O
stored	O
in	O
a	O
text	O
file	O
with	O
the	O
extension	O
"	O
.zrf	O
"	O
(	O
Zillions	O
rules	O
file	O
)	O
.	O
</s>
<s>
The	O
users	O
can	O
create	O
their	O
own	O
ZRF-files	O
and	O
make	O
the	O
AI	O
of	O
Zillions-of-Games	O
play	O
their	O
newly	O
created	O
game	O
.	O
</s>
<s>
The	O
result	O
of	O
loading	O
of	O
this	O
ZRF	B-Application
into	O
Zillions-of-Games	O
(	O
along	O
with	O
appropriate	O
images	O
)	O
and	O
playing	O
against	O
the	O
computer	O
is	O
shown	O
in	O
screenshot	O
at	O
right	O
.	O
</s>
<s>
One	O
ZRF	B-Application
can	O
contain	O
more	O
than	O
one	O
game	O
and	O
game	O
title	O
allows	O
the	O
user	O
to	O
select	O
a	O
certain	O
game	O
.	O
</s>
<s>
For	O
example	O
,	O
for	O
chess	B-Application
it	O
would	O
be	O
White	O
,	O
Black	O
.	O
</s>
<s>
The	O
definition	O
of	O
turn-order	O
can	O
be	O
more	O
complex	O
,	O
for	O
example	O
for	O
balanced	O
double-move	O
chess	B-Application
it	O
would	O
be	O
:	O
(	O
turn-order	O
White	O
repeat	O
Black	O
Black	O
White	O
White	O
)	O
,	O
which	O
specifies	O
the	O
following	O
order	O
of	O
moves	O
:	O
White	O
,	O
Black	O
,	O
Black	O
,	O
White	O
,	O
White	O
,	O
Black	O
,	O
Black	O
,	O
White	O
,	O
White	O
,	O
etc	O
.	O
</s>
<s>
Zillions	B-Application
of	I-Application
Games	I-Application
is	O
so	O
called	O
because	O
of	O
its	O
potential	O
to	O
play	O
a	O
very	O
large	O
number	O
of	O
user-programmed	O
games	O
.	O
</s>
<s>
These	O
include	O
a	O
lot	O
of	O
popular	O
board	O
games	O
,	O
such	O
as	O
Alquerque	O
,	O
Fox	O
and	O
geese	O
,	O
Go	O
,	O
Gomoku	O
,	O
Jungle	O
,	O
Halma	O
,	O
Nim	B-Application
,	O
Nine	O
men	O
's	O
morris	O
,	O
Reversi	O
,	O
Tafl	O
and	O
Tic-tac-toe	O
.	O
</s>
<s>
Besides	O
standard	O
FIDE	O
chess	B-Application
,	O
Zillions	B-Application
of	I-Application
Games	I-Application
contains	O
many	O
national	O
chess	B-Application
variants	O
such	O
as	O
shogi	O
,	O
xiangqi	O
,	O
janggi	O
,	O
as	O
well	O
as	O
a	O
number	O
of	O
popular	O
chess	B-Application
variants	O
like	O
Ultima	O
,	O
Extinction	O
chess	B-Application
,	O
Losing	O
Chess	B-Application
,	O
shatranj	O
,	O
Berolina	O
chess	B-Application
,	O
Grand	O
Chess	B-Application
and	O
others	O
.	O
</s>
<s>
It	O
also	O
include	O
some	O
puzzles	O
,	O
such	O
as	O
15-Puzzle	O
,	O
Towers	B-Language
of	I-Language
Hanoi	I-Language
,	O
eight	O
queens	O
,	O
and	O
a	O
variety	O
of	O
Solitaires	O
.	O
</s>
<s>
Not	O
long	O
after	O
it	O
came	O
to	O
market	O
in	O
late	O
1998	O
,	O
users	O
of	O
Zillions	B-Application
of	I-Application
Games	I-Application
began	O
to	O
program	O
new	O
games	O
and	O
puzzles	O
for	O
it	O
,	O
creating	O
many	O
of	O
them	O
themselves	O
.	O
</s>
<s>
Two	O
large	O
collections	O
of	O
Zillions	O
Rules	O
Files	O
(	O
ZRFs	B-Application
)	O
soon	O
began	O
to	O
appear	O
.	O
</s>
<s>
One	O
was	O
at	O
the	O
Zillions-of-Games	O
website	O
,	O
and	O
the	O
other	O
was	O
at	O
the	O
Chess	B-Application
Variant	O
Pages	O
website	O
.	O
</s>
<s>
The	O
former	O
collected	O
together	O
every	O
kind	O
of	O
ZRF	B-Application
,	O
whereas	O
the	O
latter	O
focused	O
on	O
ZRFs	B-Application
for	O
chess	B-Application
variants	O
.	O
</s>
<s>
As	O
of	O
November	O
2017	O
,	O
the	O
ZILLIONS	O
interface	O
had	O
2,577	O
ZRF	B-Application
's	O
,	O
created	O
by	O
462	O
ZRF	B-Application
authors	O
,	O
and	O
the	O
Chess	B-Application
Variant	O
Pages	O
collection	O
had	O
794	O
ZRF	B-Application
's	O
of	O
chess	B-Application
variants	O
.	O
</s>
<s>
The	O
games	O
programmed	O
by	O
the	O
users	O
include	O
such	O
games	O
as	O
4D	O
Tic-Tac-Toe	O
,	O
FreeCell	B-Application
,	O
Rubik	O
's	O
Cube	O
,	O
Teeko	O
,	O
Mancala	O
,	O
Alice	O
Chess	B-Application
,	O
Chess960	O
,	O
Hexagonal	O
chess	B-Application
,	O
Star	O
Trek	O
Tridimensional	O
Chess	B-Application
and	O
Sokoban	B-Device
.	O
</s>
<s>
Besides	O
various	O
games	O
and	O
puzzles	O
,	O
there	O
are	O
also	O
educational	O
ZRFs	B-Application
,	O
such	O
as	O
the	O
cellular	O
automata	O
Game	O
of	O
Life	O
,	O
a	O
calculator	O
,	O
and	O
some	O
Turing	B-Architecture
machine	I-Architecture
simulations	O
.	O
</s>
<s>
Zillions	B-Application
of	I-Application
Games	I-Application
can	O
be	O
used	O
for	O
the	O
following	O
:	O
</s>
<s>
The	O
available	O
win	O
,	O
loss	O
,	O
and	O
draw	O
conditions	O
include	O
checkmate	B-Application
,	O
stalemate	O
,	O
repetition	O
,	O
piece	O
capture	O
,	O
absolute	O
configuration	O
,	O
relative	O
configuration	O
,	O
and	O
various	O
types	O
of	O
piece	O
count	O
.	O
</s>
<s>
Zillions	O
includes	O
a	O
"	O
random	O
player	O
"	O
which	O
selects	O
from	O
its	O
available	O
moves	O
at	O
random	O
;	O
this	O
can	O
be	O
used	O
to	O
simulate	O
dice	O
in	O
race	O
games	O
and	O
Backgammon	B-Application
relatives	O
.	O
</s>
<s>
Despite	O
its	O
versatility	O
,	O
Zillions	B-Application
of	I-Application
Games	I-Application
has	O
a	O
number	O
of	O
non-trivial	O
limitations	O
:	O
</s>
<s>
Zillions	B-Application
Of	I-Application
Games	I-Application
is	O
designed	O
to	O
play	O
perfect	O
information	O
games	O
exclusively	O
.	O
</s>
<s>
This	O
renders	O
it	O
of	O
little	O
or	O
no	O
use	O
in	O
fairly	O
playing	O
imperfect	O
or	O
hidden	O
information	O
games	O
against	O
the	O
AI	O
,	O
such	O
as	O
card	O
games	O
or	O
board	O
games	O
with	O
hidden	O
piece	O
values	O
like	O
Stratego	B-Application
.	O
</s>
<s>
Consequently	O
,	O
in	O
shogi	O
,	O
for	O
example	O
,	O
it	O
cannot	O
be	O
programmed	O
to	O
always	O
accurately	O
enforce	O
the	O
rule	O
against	O
checkmating	B-Application
a	O
King	O
with	O
a	O
Pawn	O
drop	O
.	O
</s>
<s>
Many	O
multi-person	O
chess	B-Application
variants	O
cannot	O
be	O
played	O
because	O
it	O
will	O
immediately	O
stop	O
the	O
game	O
when	O
the	O
first	O
player	O
is	O
checkmated	O
or	O
stalemated	O
.	O
</s>
