The field of digital music authoring provides a wealth of creative environments in which music can be created and authored: patchers, programming languages, and multi-track sequencers. By combining the i-score interactive sequencer to the LibAudioStream audio engine, a new music software able to represent and play rich interactive audio sequences is introduced. We present new stream expressions compatible with the LibAudioStream, and use them to create an interactive audio graph: hierarchical stream and send-return streams. This allows to create branching and arbitrarily nested musical scores, in an OSC-centric environment. Three examples of interactive musical scores are presented: the recreation of a traditional multi-track sequencer, an interactive musical score, and a temporal effect graph.