Answer: squarethecircle

AnswerCrossword Clue
SQUARETHECIRCLE

Try a mission impossible.

SQUARETHECIRCLE

Do the impossible

SQUARETHECIRCLE

Accomplish the impossible

SQUARETHECIRCLE
An instruction impossible to fulfill
SQUARETHECIRCLE
Math professor's "impossible" command
SQUARETHECIRCLEImpossible math instruction
SQUARETHECIRCLEImpossible task