Representation Dark/Light cycles on a 2D plot

Hi, I have a kinetic over the time. I want to put on this graph the day and the night with periodic rectangular surface. For exemple time 0 is 18h and the dark cycle begin at 18h during 12h. Si i want to put a rectangle of 12h (in axis) every 24h.

Do you know a simple method to do a lot of plot like that ? Thanks a lot,