PS: Frick and Frack

Frick and Frack were famous duo of Swiss comedy ice skaters, whose stage names these were. They came to public fame in the later years of a series of skating spectaculars called Ice Follies, promoted by Eddie Shipstad and his brother Roy, which began in 1936 and ran for almost 50 years.

PS
And from my newly acquired Merriam-Webster's Dictionary of Allusions by Elizabeth Webber and Mike Feinsilber (Merriam-Webster, Springfield, Mo., 1999): Their real names were Werner Groebli (Frick) and Hans Mauch (Frack).