Used to do this when we had LP's...glue two songs together on cassette that never existed in the real world. Remember when mix tapes were actually on tape?
...had to put a nickle on top of the record and then mark where it was in the rotation when the instant the song started, so you'd know when to take your finger off the "PAUSE" button on the cassette deck...
Black Sabbath, Mob Rules - 1981 - guitar solo before Mob Rules was called E5150
right at the instant when Mob Rules was supposed to start...
...I glued in "I Don't Need Love" by Sammy, from Three Lock Box