main difference between an oxymoron and a paradox

An oxymoron is a phrase where two opposites are used together for an effect, sometimes emphasis, drama, or for comedic relief. Examples are act naturally, painfully beautiful, quiet presence, etc. A paradox is sort of like a brain teaser. It seems absurd and self contradictory and may be against the common beliefs. Examples: Less is more, "All animals are equal, but some are more equal than others" from Animal Farm, "War is Peace" from 1984, etc.