Complex sentence: Gacy designed his own costumes and taught himself how to apply clown makeup, although some professional clowns noted the sharp corners Gacy painted at the edges of his mouth are contrary to the rounded borders that professional clowns normally employ, so as not to scare children.
Split into simpler sentences: Gacy designed his own costumes and taught himself how to apply clown makeup. The sharp corners Gacy painted at the edges of his mouth are contrary to the rounded borders that professional clowns normally employ, so as not to scare children.