<s>
Blockade	B-Application
is	O
a	O
monochrome	O
arcade	O
video	O
game	O
developed	O
by	O
Gremlin	O
and	O
released	O
in	O
November	B-Application
1976	I-Application
.	O
</s>
<s>
It	O
was	O
the	O
first	O
of	O
what	O
would	O
become	O
known	O
as	O
"	O
snake	B-Application
games	I-Application
"	O
.	O
</s>
<s>
Using	O
four	O
directional	B-Device
buttons	I-Device
,	O
each	O
player	O
moves	O
their	O
character	O
around	O
leaving	O
a	O
solid	O
line	O
behind	O
them	O
,	O
turning	O
at	O
90	O
degree	O
angles	O
.	O
</s>
<s>
Blockade	B-Application
was	O
first	O
demonstrated	O
at	O
the	O
AMOA	O
show	O
in	O
November	B-Application
1976	I-Application
.	O
</s>
<s>
It	O
was	O
one	O
of	O
the	O
two	O
most	O
talked-about	O
arcade	O
games	O
at	O
the	O
show	O
,	O
along	O
with	O
Namco	O
's	O
electro-mechanical	O
racing	O
game	O
F-1	B-Application
demonstrated	O
by	O
Atari	O
,	O
Inc	O
.	O
Blockade	B-Application
was	O
possibly	O
the	O
most-played	O
arcade	O
game	O
at	O
the	O
show	O
.	O
</s>
<s>
Several	O
Blockade-style	O
games	O
appeared	O
soon	O
after	O
its	O
release	O
,	O
such	O
as	O
the	O
Bally	B-Device
Astrocade	I-Device
game	O
Checkmate	O
in	O
1977	O
,	O
Atari	O
's	O
Surround	B-Application
in	O
1978	O
,	O
and	O
the	O
1978	O
TRS-80	B-Device
computer	O
game	O
Worm	O
.	O
</s>
<s>
Though	O
Blockade	B-Application
did	O
not	O
reference	O
snakes	B-Application
or	O
worms	O
,	O
many	O
variants	O
were	O
themed	O
as	O
such	O
,	O
including	O
Nibbler	B-Application
and	O
Snake	B-Application
Byte	I-Application
,	O
both	O
from	O
1982	O
.	O
</s>
<s>
The	O
1997	O
Nokia	O
mobile	O
phone	O
version	O
is	O
simply	O
called	O
Snake	B-Application
.	O
</s>
<s>
Midway	O
's	O
Tron	B-Language
(	O
1982	O
)	O
included	O
a	O
single-player	O
variant	O
of	O
the	O
Blockade	B-Application
concept	O
based	O
on	O
the	O
Light	O
Cycle	O
game	O
from	O
the	B-Language
film	I-Language
.	O
</s>
<s>
This	O
led	O
to	O
Blockade-style	O
games	O
sometimes	O
being	O
called	O
Tron	B-Language
or	O
light	O
cycles	O
.	O
</s>
