Complex sentence: Having briefly lived with and partied with many Pranksters coincidently the Pranksters have been working on their own Time-Travel theories involving LSD and Einsteins theory of relativity.
Split into simpler sentences: Having briefly lived with and partied with many Pranksters. Coincidently the Pranksters have been working on their own Time-Travel theories involving LSD and Einsteins theory of relativity.