The M24 and Monster groups mentioned in the article are examples of the "sporadic" groups, which are 26 exceptional finite simple groups. John Conway (mentioned

The M24 and Monster groups mentioned in the article are examples of the "sporadic" groups, which are 26 exceptional finite simple groups. John Conway (mentioned in the article, inventor of his game of life) discovered four of these groups, Co0, Co1, Co2 and Co3. It's notable that the Mathieu Groups (like M24) were discovered in the 19th century, long before any other sporadic group was known. http://en.wikipedia.org/wiki/Sporadic_group http://en.wikipedia.org/wiki/Sporadic_group