The sandwich is used as a recurring gag, occasionally replaced with other types of filling for variety.
During this time, Parlow remained the head of the quartet, but the other performers were occasionally replaced.
He was occasionally replaced by Will Peterson, who made an important interception in the end zone.
The cobalt-60 isotope has a half-life of 5.3 years so the cobalt-60 needs to be replaced occasionally.
Individual flowers are reddish-purple and are occasionally replaced by bulbils (again making this a potentially invasive species).
The reactor fuel rods are occasionally replaced by removing them from the top of the containment vessel.
The duck was also occasionally replaced with a wooden Indian figure.
Vodka is occasionally replaced with gin, tequila or rum, though the Clamato may not be substituted.
American cultural and political jokes are occasionally replaced with local references.
Some of the daily strips were occasionally replaced by prose chapters.
