
Then as a MENTAL exercise,
I invite you to figure out...
The Big Bang Theory Season 4, Episode 22

Well, clearly MENTAL tasks are not enough.
The Big Bang Theory Season 10, Episode 22

And with that MENTAL picture,
I think we're done for the evening.
The Big Bang Theory Season 4, Episode 4

You need to push your brain out of its
comfort zone and reach MENTAL exhaustion.
The Big Bang Theory Season 10, Episode 22

who don't have MENTAL problems.
The Big Bang Theory Season 9, Episode 10