In the episode Lesser of Two Evils, they go to past-o-rama(a "fair" ) and they dont know what is in that sine(about parking)in normal letters, but they use normal letters in the show, and they know what it is, they use it on Slurm, the planet express symbol, the tittle: past-o-rama on tv, the unbendable gerter whit the word unbendable, the titanic magazine, the names in the head jars, the mars university tittle and the robot house tittle...
So... it's confusing, Matt Groening didnt think about that... No ofense but sometimes he forgets important details, I know he has other things to think about but...