Hi, this can also refer to trellises in elaborate gardens. You can have a look: http://shopping.msn.com/results/arbors-trellises/bcatid5301/gardman-usa/2-4557497/forsale?text=category:arbors-trellises+Brand:Gardman

Hello Phoebe, round finial: round is circular shape and finial is a crowning ornament to beautify the summit of a building specially in Gothic architecture ,so it is about a round ornament at the upper or outermost point of a building. inset: It has several meanings: - a place where something flows in like a channel or - something small that is included in something bigger such as : * a small picture inserted into the bounds of a larger one. * a piece of material or cloth inset to enlarge or strengthen a garment. * an artifact that is inserted ( and this last definition is more likely to fit into the context with "round finial".