Collective flow from ultra-relativistic heavy-ion collisions is an important hadronic observable sensitive to the early stages of system evolution. We have calculated flow components from a tilted, ellipsoidally expanding source and investigated the dependence of flow pattern on the initial geometry of the fireball. We also pointed out possible problems connected to the experimental techniques used for the calculation of the v n Fourier coefficients, which may lead to serious inaccuracy in the flow analysis.