The wheel was a great idea.
Relativity was a great idea.
The Big Bang Theory Season 1, Episode 7
Just explaining the theory of RELATIVITY.
The Big Bang Theory Season 6, Episode 5
Einstein's RELATIVITY equations
pop out.
The Big Bang Theory Season 11, Episode 13
...of the equations of general RELATIVITY
and hydrodynamics...
The Big Bang Theory Season 6, Episode 24
When Einstein came up
with special RELATIVITY...
The Big Bang Theory Season 3, Episode 14