periodic solution in which the initial Stokes waves (the starting guess) are B and C in Figure \[fig:bif:stokes\] instead of A and C. As before, solution C is shifted by $\pi$ when the waves are combined initially, just as in (\[eq:AandC\]). Because the amplitude of the larger wave has been reduced, the difference in wave speeds is smaller, and it takes much longer for the waves to collide. If the waves did not interact, we would have $$\label{eq:cBcC}
  c_{B,0} = 0.23246089, \quad c_{C,0} = 0.22808499, \quad
  T_0 = \frac{2\pi}{c_{B,0}-c_{A,0}} = 1435.86,$$ where wave B crosses the domain $53.1230$ times in time $T_0$ while wave C crosses the domain $52.1230$ times. The subscript 0 indicates that the waves are assumed not to interact. Since the waves do interact, we have to evolve the solution numerically to obtain useful estimates of $T$ and $\theta$. We arbitrarily rounded $T_0$ to 1436 and made plots of the solution at times $\Delta t = T_0/1200$. We found that $\eta$ is nearly even (up to a spatial phase shift) for the first time at $463\Delta t=554.057$. This was our initial guess for $T/2$. The phase shift required to make $\eta(x+\theta/2,T/2)$ approximately even and $\varphi(x+\theta/2,T/2)$ approximately odd 