<s>
Fruit	O
is	O
a	O
chess	B-Application
engine	I-Application
developed	O
by	O
Fabien	O
Letouzey	O
.	O
</s>
<s>
At	O
the	O
World	O
Computer	O
Chess	O
Championship	O
in	O
Reykjavík	O
in	O
2005	O
,	O
Fruit	O
2.2	O
scored	O
8.5	O
out	O
of	O
11	O
,	O
finishing	O
in	O
second	O
place	O
behind	O
Zappa	B-Application
.	O
</s>
<s>
Until	O
Version	O
2.1	O
(	O
Peach	O
)	O
,	O
Fruit	O
was	O
free	B-License
and	I-License
open-source	I-License
software	I-License
subject	O
to	O
the	O
requirements	O
of	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
and	O
as	O
such	O
contributed	O
much	O
to	O
the	O
development	O
in	O
computer	O
chess	O
in	O
recent	O
years	O
.	O
</s>
<s>
Some	O
people	O
still	O
work	O
on	O
the	O
v2.1	O
source	O
code	O
and	O
have	O
created	B-Application
variations	I-Application
from	O
the	O
original	O
Fruit	O
.	O
</s>
<s>
As	O
of	O
July	O
23	O
,	O
2007	O
,	O
Fruit	O
became	O
freeware	B-License
.	O
</s>
<s>
Fruit	O
2.3.1	O
was	O
one	O
of	O
the	O
top	O
3	O
free	O
UCI	B-General_Concept
chess	B-Application
engines	I-Application
.	O
</s>
<s>
Fruit	O
uses	O
the	O
classical	O
Negascout	B-General_Concept
(	O
principal	B-General_Concept
variation	I-General_Concept
search	I-General_Concept
)	O
algorithm	O
with	O
iterative	B-Algorithm
deepening	I-Algorithm
to	O
traverse	O
the	O
game	O
tree	O
.	O
</s>
<s>
It	O
also	O
uses	O
the	O
null-move	B-Algorithm
heuristic	I-Algorithm
.	O
</s>
<s>
The	O
original	O
version	O
used	O
a	O
simplistic	O
evaluation	B-General_Concept
function	I-General_Concept
with	O
a	O
robust	O
search	O
.	O
</s>
<s>
Later	O
versions	O
have	O
improved	O
evaluation	B-General_Concept
functions	I-General_Concept
.	O
</s>
<s>
The	O
board	B-General_Concept
representation	I-General_Concept
is	O
distinct	O
—	O
Fruit	O
uses	O
a	O
16x16	O
board	O
.	O
</s>
<s>
Although	O
in	O
2007	O
Fabien	O
Letouzey	O
stopped	O
the	O
development	O
of	O
Fruit	O
with	O
version	O
2.3.1	O
,	O
the	O
earlier	O
open	B-Application
source	I-Application
2.1	O
version	O
provided	B-Application
the	I-Application
basis	I-Application
for	O
many	O
other	O
programs	O
.	O
</s>
<s>
Toga	B-Application
II	I-Application
is	O
a	O
derivative	O
created	O
by	O
Thomas	O
Gaksch	O
,	O
currently	O
continued	O
by	O
Jerry	O
Donald	O
Watson	O
.	O
</s>
<s>
The	O
strongest	O
version	O
is	O
Toga	B-Application
II	I-Application
4.0	O
,	O
released	O
on	O
29	O
December	O
2017	O
by	O
Jerry	O
Donald	O
Watson	O
.	O
</s>
<s>
Experimental	O
versions	O
of	O
Toga	B-Application
II	I-Application
running	O
on	O
computer	B-Architecture
clusters	I-Architecture
have	O
competed	O
in	O
the	O
World	O
Computer	O
Chess	O
Championship	O
(	O
WCCC	O
)	O
.	O
</s>
<s>
At	O
about	O
80	O
ELO	O
above	O
Fruit	O
2.3.1	O
,	O
Toga	B-Application
II	I-Application
is	O
the	O
strongest	O
Fruit	O
derivative	O
.	O
</s>
<s>
In	O
2008	O
,	O
forks	B-Application
of	O
Toga	B-Application
II	I-Application
started	O
to	O
appear	O
,	O
like	O
Grapefruit	O
and	O
Cyclone	O
.	O
</s>
<s>
GambitFruit	B-Application
is	O
another	O
free	O
derivative	O
of	O
Fruit	O
2.1	O
,	O
created	O
by	O
Ryan	O
Benitez	O
.	O
</s>
<s>
GambitFruit	B-Application
also	O
incorporates	O
improvements	O
from	O
Toga	B-Application
II	I-Application
.	O
</s>
<s>
Development	O
of	O
GambitFruit	B-Application
stopped	O
in	O
2005	O
.	O
</s>
<s>
GNU	B-Application
Chess	I-Application
6.x	O
is	O
based	O
on	O
Fruit	O
2.1	O
and	O
the	O
project	O
is	O
since	O
2011	O
under	O
active	O
development	O
.	O
</s>
<s>
Fruit	O
Reloaded	O
by	O
Fabien	O
Letouzey	O
,	O
Daniel	O
Mehrmann	O
and	O
Ryan	O
Benitez	O
is	O
an	O
independent	O
fork	B-Application
of	O
Fruit	O
2.1	O
with	O
a	O
number	O
of	O
enhancements	O
.	O
</s>
<s>
In	O
June	O
2011	O
,	O
a	O
lengthy	O
investigation	O
by	O
the	O
International	O
Computer	O
Games	O
Association	O
(	O
ICGA	O
)	O
determined	O
Rybka	B-Application
was	O
plagiarized	O
from	O
Fruit	O
and	O
Crafty	B-Application
.	O
</s>
<s>
The	O
author	O
of	O
Rybka	B-Application
,	O
Vasik	O
Rajlich	O
,	O
refused	O
to	O
address	O
the	O
allegations	O
against	O
Rybka	B-Application
with	O
the	O
ICGA	O
,	O
instead	O
preferring	O
an	O
ex	O
post	O
facto	O
public	O
interview	O
conducted	O
by	O
Nelson	O
Hernandez	O
on	O
July	O
4	O
,	O
2011	O
.	O
</s>
<s>
Senpai	O
makes	O
use	O
of	O
chess	B-Application
engine	I-Application
developments	O
made	O
in	O
the	O
intervening	O
decade	O
.	O
</s>
<s>
It	O
differs	O
from	O
Fruit	O
in	O
using	O
bitboards	O
and	O
11	O
's	O
thread	O
support	O
for	O
SMP	B-Operating_System
.	O
</s>
