I am creating an animation of tears using the formula y=ax^2.
This is the case with only tears in the right eye. The tears that clone the parabola of y=(-1/100)x^2 move. I adjust it so that x=0 is exactly at the eye position, then reduce x by 3 and remove it when the tears reach the edge of the screen.
Tokyo-syoseki New Math 3
Page 114 Parabola around us