As we watched, gentle ripples ruffled the surface of Arethusa Pool, smudging reflections of the fringing native vegetation, so the lake looked like liquid pounamu, the greenstone gem treasured by New Zealand Māori. Two tiny rocky islands, resembling bonsai landscapes, adorned the lake like the upper-most decorations on a tiered wedding cake – for they are islands in a lake, on an island in a lake, on an island in the ocean.