How to Create Impossible Geometry Shapes in Adobe Illustrator (with Triangles & Circles)
Create Mind-Bending Impossible Geometry in Illustrator — No 3D Tools Needed
Impossible geometry—those surreal shapes that look like they defy gravity or logic—can seem intimidating to draw in Illustrator. But with the right tools and techniques, they’re totally doable. In this two-part tutorial, I’ll show you how to build both triangle-based and circular impossible shapes using only vector tools, smart spacing, and the Shape Builder.
No 3D tools. No plug-ins. Just pure Illustrator magic. ✨
You can check out this video (and lots more!) over on my Instagram Page @hannah.bacon.design
Part 1: Triangle-Based Impossible Geometry
Straight-edged impossible shapes (like Penrose triangles) require precise spacing and careful construction—but once you understand the flow, it becomes surprisingly intuitive.
Overview of the Process:
Start simple: Draw a triangle and copy-paste it in place
Use the Appearance Panel → Path → Offset Path (with a negative value) to create inner outlines
Repeat with even spacing
Add evenly spaced guide lines that match the angles of your triangle (e.g. 60°)
Use the Transform Panel to rotate and reflect those lines accurately
With the Pen Tool, add necessary edge lines to “complete” the illusion
Use the Shape Builder Tool (Shift + M) to define individual segments
Clean up the outer lines, then add gradients for dimensional shading
Part 2: Circular Impossible Shapes (Rounded Geometry)
Circular or rounded impossible shapes are often easier to manage than angular ones, thanks to the predictable arc of the curves.
Overview of the Process:
Start with a circle, then copy-paste in place
Offset the inner path using the Appearance Panel → Offset Path, then expand
Alt + Drag a copy inward and align it
Add horizontal lines across the top and bottom to divide segments
Use the Shape Builder Tool to carve out the interlocking shapes
Clean up excess lines
Swap colours, and apply a stroke that matches the background for subtle separation
This creates that beautiful interwoven illusion, where the segments appear to pass behind and in front of each other.
Want More Time-Saving Tools and Freebies?
This process is just one of the techniques I share across my design templates and digital assets, made especially for designers who want professional results—without starting from scratch every time.
