It is a bit like neo4j's cypher, (2) is an edge, like a circle, [2] is a label, like in a property graph.

  (Alice)--[loves]-->(Bob)
  
  (loves)--[type]-->(Property)
         --[domain]-->(Human)
         --[range]-->(Human)
  
  (type)--...

Sort of like that, cypher does not support this type of expression though.