I want to use the pen tool to form two lines which are perpendicular. However when I make a line and then continue to click the third point to form an L shape, Illustrator automatically forms a polygon.

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  • 1
    You have a fill selected. Set the fill to none, and set a stroke instead.
    – Billy Kerr
    Dec 23, 2019 at 11:09

2 Answers 2


The pen tool forms a path. It looks like you have a dark blue fill in your stroke and fill settings. Change the fill to "no fill" and you should just see the paths (with whatever stroke you have set). Any open path (which is not a closed shape) will fill even without being closed.

  • ..... and open paths can create all sorts of havoc upon output. You should *always strive to close paths if they have a fill.
    – Scott
    Dec 23, 2019 at 8:06

It is how the Pen Tool works. If you click 100 times, it will create a 100-point shape with connected segments, which can look like a polygon if you have a fill color applied. With the object selected, hit Shift+X to reverse the fill into a stroke and make it look like an actual 'L'.

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