Dave Richeson on Twitter: "What was I doing while listening to the inauguration? Folding Steffan's polyhedron—a nonconvex polyhedron that is flexible, not rigid. (It took a few tries.) I used Laszlo Bardos's
![Graphic statics & kinematics analysis for the Steffen flexible polyhedron. | Download Scientific Diagram Graphic statics & kinematics analysis for the Steffen flexible polyhedron. | Download Scientific Diagram](https://www.researchgate.net/publication/320215110/figure/fig4/AS:614150325669888@1523436256071/Graphic-statics-kinematics-analysis-for-the-Steffen-flexible-polyhedron.png)
Graphic statics & kinematics analysis for the Steffen flexible polyhedron. | Download Scientific Diagram
![Steffen's Flexible Polyhedron Has 14 Triangular Faces, - Strongest Shape - Free Transparent PNG Clipart Images Download Steffen's Flexible Polyhedron Has 14 Triangular Faces, - Strongest Shape - Free Transparent PNG Clipart Images Download](https://www.clipartmax.com/png/small/235-2352846_steffens-flexible-polyhedron-has-14-triangular-faces-strongest-shape.png)
Steffen's Flexible Polyhedron Has 14 Triangular Faces, - Strongest Shape - Free Transparent PNG Clipart Images Download
![Schönhardt's twisted octahedron. Lemma 2.3. The polyhedron from Example... | Download Scientific Diagram Schönhardt's twisted octahedron. Lemma 2.3. The polyhedron from Example... | Download Scientific Diagram](https://www.researchgate.net/publication/45878521/figure/fig1/AS:669502429724677@1536633226495/Schoenhardts-twisted-octahedron-Lemma-23-The-polyhedron-from-Example-22-is.png)
Schönhardt's twisted octahedron. Lemma 2.3. The polyhedron from Example... | Download Scientific Diagram
![Twitter \ Frank Nielsen على تويتر: "Can you deform a 3D polyhedron with *hinged edges* and rigid faces? Never when it is convex but possible (although rare) for non-convex polyhedra. Flexible polyhedra Twitter \ Frank Nielsen على تويتر: "Can you deform a 3D polyhedron with *hinged edges* and rigid faces? Never when it is convex but possible (although rare) for non-convex polyhedra. Flexible polyhedra](https://pbs.twimg.com/media/EZym6oYUYAAF9_A.jpg:large)
Twitter \ Frank Nielsen على تويتر: "Can you deform a 3D polyhedron with *hinged edges* and rigid faces? Never when it is convex but possible (although rare) for non-convex polyhedra. Flexible polyhedra
![Graphic statics & kinematics analysis for the Steffen flexible polyhedron. | Download Scientific Diagram Graphic statics & kinematics analysis for the Steffen flexible polyhedron. | Download Scientific Diagram](https://www.researchgate.net/profile/Marina-Konstantatou-2/publication/320215110/figure/fig4/AS:614150325669888@1523436256071/Graphic-statics-kinematics-analysis-for-the-Steffen-flexible-polyhedron_Q320.jpg)