
Not lima beans. Carbon atoms.
The Big Bang Theory Season 3, Episode 14

I don't know. How do CARBON atoms
form a benzene ring?
The Big Bang Theory Season 2, Episode 13

...while I build CARBON atoms.
The Big Bang Theory Season 3, Episode 14

But just because
you've got some CARBON
The Big Bang Theory Season 5, Episode 12

Carbon.
The Big Bang Theory Season 12, Episode 23