English: This schematic illustrates the wide range of unique structures observed in this remarkable nebula. A thick dust disc obscures the starlight from the central binary star system. Constrained starlight passes into the bipolar nebula lobes, seen almost face-on. Multiple episodes of mass-loss have created a series of nested paraboloids in which the gas surfaces are seen edge-on as ”ladder rungs” with bright vortex-like features at their lateral edges. In infrared wavelengths, the nebula does not shine by reflected starlight but emits broad and narrow unidentified molecular bands.