[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is an allotrope of carbon with molecular formula C18 existing as a ring of eighteen carbon atoms, connected by alternating triple and single bonds. It is an elemental carbon and a carbocyclic compound."}, {"from": "gpt", "value": "[C][#C][C][#C][C][#C][C][#C][C][#C][C][#C][C][#C][C][#C][C][#C][Ring2][Ring1][C]"}]