Answer: SQUARETHECIRCLE

AnswerCrossword Clue
SQUARETHECIRCLETry a mission impossible.
SQUARETHECIRCLEDo the impossible
SQUARETHECIRCLEAccomplish the impossible
SQUARETHECIRCLEAn instruction impossible to fulfill
SQUARETHECIRCLEMath professor's "impossible" command
SQUARETHECIRCLEImpossible math instruction
SQUARETHECIRCLEImpossible task