sample.scm

(EvaluationLink
  (Predicate "is_part")
  (List
    (Concept "A")
    (Concept "B"))
)

(EvaluationLink
  (Predicate "is_part")
    (List
      (Concept "A")
      (Concept "C"))
)

(EvaluationLink
  (Predicate "is_part")
    (List
      (Concept "C")
      (Concept "D"))
)

(EvaluationLink
  (Predicate "is_part")
    (List
      (Concept "A")
      (Concept "E"))
)