The professor at the seminar notices that one of the students is not completely sober. He says to him:
Students, you are drunk. Leave the workshop immediately!
What are you, Professor? I am completely sober!
Are you sober? Then write me the formula for calculating laplasian in toroidal coordinates.
The student goes out to the board and writes a long formula. The professor checks the manual for a long time and ensures that everything is written correctly.
Well, I am impressed! I don’t remember this formula and I can’t remember it with a sober head.
The student:
I was sober and I don’t remember.