Cited from http://www.ds.mpg.de/english/research/dept_FPN/chaos/spirals/: Spiral patterns are found in many patternforming systems. Famous examples include cardiac arrhythmias of the heart, the aggregation of starving slime mold amoebae, and the Belousov-Zhabotinsky chemical reaction. Many of these systems can be classified as excitable media in which the core of the spiral, like a pacemaker, selects the temporal and spatial evolution of the outward travelling spiral waves. We conducted a detailed experimental study of a driven, dissipative system in which the formation of spirals can be attributed to a qualitatively different mechanism acting far away from the spiral's core. In particular, we show for Rayleigh-Bénard convection of a small Prandtl number fluid that the rotation of giant, multi-armed spirals can be captured using concepts based on nonlinear phase equations.