Professor : "Now we need only one more thing"
Assistant : "All right, then I'll go and buy one—"
Professor : "Stop!"
Assistant : "What?? But..."
Professor : "I said 'stop', didn't you hear me?"
Assistant : "Oh dear... what do we need, professor?"
a | k | b | f | o | r |
t | y | e | i | g | p |
h | t | z | q | u | m |
v | o | a | r | x | j |
l | n | y | g | e | d |
e | s | h | r | b | y |
Now, what do they need?
Answer: