What I'm trying to do

Here is an interaction from my last project. Showing how I want the interaction to work with the exception of it being the 'light' rather than the line used here. I am still having trouble with my own design as even though I have released the mouse button it doesn't restart the 'light' It just carries on the rest of the 'light' and then nothing else happens. I'm looking into arrays and looping but am not exactly sure how to go about it. But we shall see.