Soap bubbles on a dodecahedral frame. Bubble films always attempt to occupy the minimum surface area when stretched between two lines, and they meet other films at straight lines. This frame contained the minimum surface area configuration, but a bubble was blown into the centre of it. With bubble frames with fewer sides than this, its internal pressure gives the inner bubble significantly curved sides. In this frame, however, the inner bubble's shape is nearly spherical anyway, and the internal pressure does not significantly distort it from the flat-faced geometry.