<s>
Actor-Lab	B-Application
is	O
a	O
program	O
that	O
visualizes	O
the	O
Lego	B-Application
Mindstorms	I-Application
internal	O
logic	O
through	O
visual	O
flowcharts	B-Language
.	O
</s>
<s>
The	O
ideas	O
underlying	O
actor-lab	B-Application
are	O
derived	O
from	O
the	O
event-driven	O
,	O
message-passing	O
computer	B-Language
languages	I-Language
that	O
began	O
with	O
the	O
actor	O
based	O
languages	O
devised	O
by	O
Hewit	O
.	O
</s>
<s>
Actor-lab	B-Application
requires	O
constant	O
communication	O
with	O
a	O
programmable	O
brick	O
(	O
e.g.	O
</s>
<s>
Actor-lab	B-Application
shows	O
the	O
user	O
in	O
real-time	O
what	O
is	O
happening	O
on	O
the	O
programmable	O
brick	O
,	O
including	O
simulation	O
of	O
motors	O
,	O
sensors	O
,	O
lights	O
,	O
and	O
sounds	O
.	O
</s>
<s>
There	O
is	O
a	O
similar	O
program	O
from	O
Lego	O
called	O
Robolab	B-Application
,	O
where	O
one	O
can	O
actually	O
download	O
programs	O
to	O
the	O
Lego	O
programmable	O
brick	O
.	O
</s>
