Connect Lines is a puzzle game in which the goal is to rotate line-segments so that together they form a continuous connected path or network i.e. all the lines must join up into one single connected structure.
It is simple in appearance but grows challenging, because you must figure out the correct orientation of each piece so that the network is complete without any breaks.
As the puzzle advances, the arrangement / layout becomes more complex. The number of line-pieces increases, the shapes become more varied, and finding the correct connection scheme becomes harder. You may need to think ahead about how rotating one piece will affect connections with several adjacent pieces. (This is standard for these kinds of puzzles.)