Distribution of mass ratio (top) and initial tilt angle (bottom) as functions of time before collision. The left and right panels show the models with varied density and varied shape, respectively. Collisions that occur before 5 h have elapsed are excluded from this plot. For the remaining simulations shown in the figure, the average time it takes to collide is 143 h, 166 h, and 133 h for models D1, D2, and D3, respectively, while the average is 171 h, 193 h and 79 h for models S1, S2, and S3 models, respectively.