About this game
Fill Line is a calm, minimalist brain teaser where the goal is to connect every square on the grid with one continuous line. The idea is easy to grasp in seconds, but the puzzles quickly get tricky as the grids expand and the routes twist around each other. Every level asks you to think a few moves ahead and picture how the path will travel through the remaining space.
The game offers thousands of levels, starting with small 4x4 layouts that teach the basics and moving toward expert challenges that will test your spatial reasoning. There is also a daily puzzle to keep your mind active. With no timer pressing down on you, you can take your time, experiment with different routes, and enjoy the quiet satisfaction of finding the solution.
The main rule to remember is that your line can never cross itself, and you cannot step onto a square you have already filled. These constraints make every decision meaningful. Whether you are looking for a short break or a longer session of focused thinking, Fill Line is a simple and rewarding way to sharpen your logic.
How to play
Tap or click the designated starting block, then drag your finger or cursor across the grid to fill all the remaining blocks. Your line cannot overlap itself, and you cannot revisit a block you have already filled. The game works on touch screens and with a mouse.