<s>
The	O
Digi-Comp	B-Device
II	I-Device
was	O
a	O
toy	O
computer	O
invented	O
by	O
John	O
"	O
Jack	O
"	O
Thomas	O
Godfrey	O
(	O
1924	O
–	O
2009	O
)	O
in	O
1965	O
and	O
manufactured	O
by	O
E.S.R.	O
,	O
Inc	O
.	O
in	O
the	O
late	O
1960s	O
that	O
used	O
marbles	O
rolling	O
down	O
a	O
ramp	O
to	O
perform	O
basic	O
calculations	O
.	O
</s>
<s>
The	O
red	O
plastic	O
cams	O
played	O
the	O
part	O
of	O
flip-flops	B-General_Concept
in	O
an	O
electronic	O
computer	O
-	O
as	O
a	O
marble	O
passed	O
one	O
of	O
the	O
cams	O
,	O
it	O
would	O
flip	O
the	O
cam	O
around	O
-	O
in	O
one	O
position	O
,	O
the	O
cam	O
would	O
allow	O
the	O
marble	O
to	O
pass	O
in	O
one	O
direction	O
,	O
in	O
the	O
other	O
position	O
,	O
it	O
would	O
cause	O
the	O
marble	O
to	O
drop	O
through	O
a	O
hole	O
and	O
roll	O
to	O
the	O
bottom	O
of	O
the	O
ramp	O
.	O
</s>
<s>
The	O
Digi-Comp	B-Device
II	I-Device
platform	O
measures	O
.	O
</s>
<s>
The	O
Digi-Comp	B-Device
II	I-Device
was	O
not	O
programmable	O
,	O
unlike	O
the	O
Digi-Comp	O
I	O
,	O
an	O
earlier	O
offering	O
in	O
the	O
E.S.R.	O
</s>
<s>
Computer	O
scientist	O
Scott	O
Aaronson	O
analyzed	O
the	O
computational	O
power	O
of	O
the	O
Digi-Comp	B-Device
II	I-Device
.	O
</s>
<s>
Aaronson	O
showed	O
that	O
this	O
decision	O
problem	O
,	O
given	O
as	O
inputs	O
a	O
description	O
of	O
the	O
DAG	O
and	O
the	O
number	O
of	O
balls	O
to	O
run	O
(	O
encoded	O
in	O
unary	O
)	O
,	O
is	O
complete	O
under	O
log-space	B-Algorithm
reduction	I-Algorithm
for	O
CC	O
,	O
the	O
class	O
of	O
problems	O
log-space	B-Algorithm
reducible	I-Algorithm
to	O
the	O
stable	O
marriage	O
problem	O
.	O
</s>
<s>
A	O
slightly	O
downscaled	O
reproduction	O
of	O
the	O
Digi-Comp	B-Device
II	I-Device
,	O
made	O
from	O
plywood	O
,	O
is	O
available	O
from	O
Evil	O
Mad	O
Scientist	O
since	O
2011	O
.	O
</s>
