  The considerable influx of new data on B decays offers opportunities to
determine some of the smaller contributions to the decay process, such as
suppressed diagrams, and to test the relations between decay amplitudes implied
by (broken) SU(3) symmetry. The graphical decomposition of decay amplitudes,
corrected here for the contribution of electroweak penguins following Gronau,
Rosner et al, implies bounds not only on the size of diagram contributions but
also on the relevant complex phases due to Cabbibo-Kobayashi-Maskawa matrix
factors. The available data on B decays to two charmless pseudoscalar mesons
are analysed to study some of these decay amplitude relations, and allowed
values of $\gamma=Arg(V_{ub}^*)$ which are consistent with the current favoured
values is obtained. Our analysis is based on a graphical approach, which offers
some insight that is difficult to obtain from $\chi^2$ minimisation, and our
results are consistent with recent observations on the difficulty of obtaining
simultaneous fits to $K\pi$ and $\pi\pi$ decay channels. We have also analyzed
the $K\eta$ and $K\eta'$ channels, and find similar difficulties.
