Penny says they're having fun
working on the PROTOTYPE.
The Big Bang Theory Season 9, Episode 19
that allowed us to get the size
of the PROTOTYPE down to the target specs.
The Big Bang Theory Season 10, Episode 15
but we did kinda have fun
working on the PROTOTYPE.
The Big Bang Theory Season 9, Episode 19
we've put a lot of thought and effort
into this current PROTOTYPE.
The Big Bang Theory Season 10, Episode 23
...a working PROTOTYPE of the Mars Rover.
The Big Bang Theory Season 8, Episode 3