The main trait used in synthesis graph, a graph element, abbreviated as GE.
Graph elements are characterized by having a calculation rate (possibly unknown),
and they embody future UGens, which are created by invoking the expand method.
For each ugen in SuperCollider, there is a corresponding graph element defined
in the ugen package, and these elements take again graph elements as arguments.
Multi-channel expansion is thus deferred to the transition from SynthGraph to UGenGraph.
Currently, also a lot of unary and binary operations are directly defined on the GE trait,
although they might go into a separate GEOps implicit class in future versions.