anchor.diff:   (service:Layer{name:"service"}),
    (util:Layer{name:"util"})
   MERGE
  - (constraints)-[cu:LAYER_USE{allowed:true}]->(util)
  + (constraints)-[:LAYER_USE{allowed:true}]->(util)
   MERGE
    (config)-[:LAYER_USE{allowed:true}]->(security)
   MERGE
  
positive.code: 
  [[layer:ExistingRelations]]
  .Adds the relation `LAYER_USE` for all Layers which contains classes which depends on each other. Add the information `allowed`, `count` (nr of dependencies), `dependencies`.
  [source,cypher,role=concept,requiresConcepts="layer:Layer"]
  ----
  MATCH
      (L1:Layer)-[:CONTAINS*]->(t1:Type),
  
negative.code: 
  [[layer:Cycles]]
  .There must be no cyclic dependencies between layers.
  [source,cypher,role=constraint,requiresConcepts="layer:ExistingRelations, layer:WantedRelations"]
  ----
  MATCH
    (L1:Layer)-[sr:LAYER_USE]->(L2:Layer),
  