His performance was perfect and without blemish.

In mathematics, a perfect number refers to a number where the sum of its divisors, excluding the number itself, equals the number.

He is immersed in the study of panmagic squares.

This fish is completely farmed, and no capture is done in the natural environment.

Research on cold fusion is still controversial.

The development of fusion reactors could potentially be the key to solving future energy problems.

He is a perfectionist, so he is very strict about his work.

He played a perfect fifth scale on the piano.