sounding than it initially was), Chief Wiggums hair  color, and Smithers skin color (he is black in his first  appearance, but becomes yellow/caucasian in all future appearances).  Early episodes have a slightly different opening credit sequence.  After Homer tosses the radioactive rod into the street, Bart is seen  skateboarding but we do not see any recognizable characters in the  streetscape as we do later. The skateboard sequence ends by showing  a group of generic townspeople running after a bus. We then see Lisa  riding home on her bike, overloaded with schoolbooks, parking it in  the garage just before Homers car pulls into the driveway (after  which the credits continue as usual).