In this Illustrator tutorial, we’ll create the Penrose Triangle–also known as the “Impossible Triangle”-using a series of guides and simple drawing tools. We’ll then add a series of colored gradients to this shape to help build out the optical illusion factor of the triangle a little more. Whether you’re into just drawing this Penrose Triangle, or you’d like to create it digitally in Illustrator, you’ll love this tutorial!
Create Triangles and Use the Pathfinder to Create Initial Shapes
Grab the Star tool and use the down arrow key as you drag out the star to get rid of sides of the star until you have nothing but a triangle left. The goal here is to create a shape similar to what you see in the screenshot. I used a combination of Transforming, Duplicating, and the Pathfinder to create a precise series of paths that will create the perfect basis of guides in the next step.
Convert Shapes to Guides
Select all the shapes that we just created and go View>Guides>Make Guides. Also, in the View menu, make sure you have Snap to Point turned on and Smart Guides turned on as well. We now have what we need to quickly and precisely draw the shapes needed for the Penrose Triangle.
Use the Pen Tool to Draw the Shapes
Grab the Pen Tool and hover over the points and intersections as you create a series of three shapes that will make up our Penrose Triangle. For this step, you really want to watch the video at the top of this post starting at the 06:55 minute mark to see exactly where I drew my triangles.
Fill Shapes and Tweak with the Gradient Tool
Once we have our three shapes, select one of them and apply a gradient fill. Grab the Gradient tool and drag the gradient so the darker side of the gradient runs into what would look like the inner corners of the triangle illusion. Once more, check out the video at the top of this post to see exactly how this triangle and gradient effect comes together.