See also the related forms, Sidney (English and French), Sidney (English and French). Dennis is a classic favorite. Today it is still a fairly popular baby name for boys, though not to the extent it was in the past. Its usage peaked in 1946 with 1.299% of baby boys being given the name Dennis.
When we use the turn signal switch, it cancels the brake light signal, on the side selected. If it did not, the lights would stay on and not flash. A bad turn-signal switch may interrupt the brake light circuit when it should not. A broken wire to or from the switch may also cause the lower brake-lights not to work. The third brake light does not flash with turn signals.
The large cavity of the eye is filled with a jelly like substance called vitreous. When we are born it is attached to the back surface of the eye, the retina. As we age the vitreous shrinks. So at some point it has to separate from the retina. This can irritate the retina and cause flashing lights. It can also result in floating spots in our vision. This is because the vitreous surface that was against the retina is now floating in the center of the eye casting a shadow. Most of the time (99+%) this does not cause a problem.