  We present azimuthal anisotropy measurements in Au+Au and Cu+Cu collisions at
$\sqrt{s_{NN}}$ = 62.4 and 200 GeV. Comparison between reaction plane and
cumulant $v_2$ measurements in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV
show that non-flow contributions, originating mainly from jets, influence the
extracted $v_2$ for $p_T$ $\gtrsim$ 3.5 GeV/c. Number of constituent quark
(NCQ) scaling of $v_2$, when studied as a function of transverse kinetic energy
$KE_T$, is seen to hold for Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 and 200
GeV and for Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV for $KE_{T}$
$\lesssim$ 1 GeV/c. Differential hexadecupole flow $v_4$ seems to exhibit
scaling with integral $v_2$ for centrality $\le$ 40% as has been observed for
differential $v_2$.
