- name: Addition
  if:
  - (Processing ?C)
  - (Answer EMPTY ?C)
  - (Slot ?Nlower ?C ROW1)
  - (Slot ?Nupper ?C ROW2)
  - (Sum ?Nlower ?Nupper ?NAnswer)
  then:
  - (*delete (Answer EMPTY ?C))
  - (*deposit (Answer ?NAnswer ?C))
- name: ShiftColumn
  if:
  - (Processing ?C)
  - (Leftof ?Cleft ?C)
  - (Answer ?N ?C)
  - (*test-not-equal ?N EMPTY)
  then:
  - (*delete (Processing ?C))
  - (*deposit (Processing ?Cleft))
- name: Stop
  if:
  - (Processing ?C)
  - (Leftmost ?C)
  - (Answer ?N ?C)
  - (*test-not-equal ?N EMPTY)
  then:
  - (*halt)