epochs in Figure \[fig:lc\] when this brightness was observed. Half of the time interval between these two epochs gives $t_{\rm E} = 62.5~{\rm d}$. We note that the values of $u_0$ and $t_{\rm E}$ critically depend on the assumption that the blending can be neglected.

Figure \[fig:lc\] can be used to find the epoch when the source approached the first ($t_1 = 6112.4~{\rm d}$) and the second cusp ($t_2 = 6120.9~{\rm d}$). This allows one to determine the distance of the source from the lens at these two epochs in the units of $\theta_{\rm E}$: $$u(t) = \sqrt{\left(\frac{t-t_0}{t_{\rm E}}\right)^2+u_0^2}.$$ It results in $u(t_1) = 0.73$ and $u(t_2) = 0.65$. This in turn can be used to find the value of $\alpha = \arcsin(u_0/u(t_1))= 47.4^{\circ}$. However, small changes in the value of $\alpha$ can result in significant changes in the light curve shape and this value should be treated with caution.

The light curve of OGLE-2012-BLG-0406 showed two anomalies, and we assume that each of them corresponded to the source passing exactly through the cusp. Figure \[fig:traj\] can be used to validate this assumptions in the fitted model. During the second anomaly, the distance between the source and the cusp was 