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generated by hydro was too large when compared to previous heavy ion exper- iments, those at Rhic matched quite well [106]; see Fig. 2.2. Unfortunately the HBT radii were not so well reproduced; see Fig. 2.3. 

However the picture can never be this crystal clear. Hydrodynamics is a set of evolution equations; the initial conditions are input, and, not surpris- ingly, what comes out of hydro is highly dependent on what goes in; see Fig. 2.4. There have been some suggestions for testing the initial state [114, 115]; without good theoretical or, better, experimental control over the initial con- 

