<s>
3D	B-Application
Dotty	I-Application
is	O
a	O
maze	B-Application
video	I-Application
game	I-Application
written	O
by	O
J.L.	O
</s>
<s>
Harris	O
and	O
published	O
by	O
Blue	O
Ribbon	O
for	O
the	O
Acorn	B-Device
Electron	I-Device
and	O
BBC	B-Device
Micro	I-Device
home	O
computers	O
in	O
1987	O
.	O
</s>
<s>
Each	O
screen	O
consists	O
of	O
vertically	O
stacked	O
mazes	B-Application
connected	O
by	O
ladders	O
.	O
</s>
