To Kokichi Sugihara's English Top Page

Lecture Series for Those Who Stay Home

World of 3D Optical Illusion

Many people are fighting against the new coronavirus, but I cannot do anything except for just staying home. So I decided to start this series of lectures of 3D optical illusion with the hope that they could entertain those who stay home. It is my pleasure if you could enjoy them. (Related links are here.)

One general remark is that seeing videos is quite different from seeing 3D objects directly. When we see objects directly, we can use two eyes and hence can understand the depth relatively easily. On the other hand, seeing videos is essentially equivalent to seeing objects by one eys, because a video camera has only one lens center. Some of the illusions presented here do not occur when we see the objects directly. Anyway you may enjoy all of the illusions as long as you are watching the videos. [April 4, 2020]

In this series of lectures from 1 to 18 (except for Lecture 6), I showed my own theories together with my own illusion artworks. In Lecture 6, Lecture 19 and afterward, on the other hand, we choose general topics on 3D optical illusion that are known in this research area. In those cases also I use original material that I create myself. [July 28, 2020]


Lecture 1. Right-Facing Arrow
   
Comments on Lecture 1
   
Gallery of Facing-Right Objects



Lecture 2. Anti-Gravity Slopes

   Comments on Lecture 2
   
Gallery of Anti-Gravity Slopes



Lecture 3. Height-Reversing Staircase

   Comments on Lecture 3
   
Gallery of Height-Reversing Staircases



Lecture 4. Penrose Triangle

   Comments on Lecture 4
   
Gallery of Anomalous Objects



Lecture 5. Circular Rectangle

   Comments on Lecture 5
   
Gallery of Ambiguous Objects Made by Circular Rectangles



Lecture 6. Multiple Silhouette Objects

   Comments on Lecture 6
   
Gallery of Multiple Silhouette Objects



Lecture 7. Height-Reversing Objects

   Comments on Lecture 7
   
Gallery of Height-Reversing Objects



Lecture 8. Invisible Chicken

   Comments on Lecture 8
   
Gallery of Partly Invisible Objects



Lecture 9. Ambiguous Cylinders

   Comments on Lecture 9
   
Gallery of Ambiguous Cylinders



Lecture 10. Topology-Disturbing Objects

   Comments on Lecture 10
   
Gallery of Topology-Disturbing Objects



Lecture 11. Card Marks Floating on a Mirror

   Comments on Lecture 11
   
Gallery of Reflexively-Fused Objects



Lecture 12. Paper-Made Ambiguous Cylinders

   Comments on Lecture 12
   
Gallery of Paper-Made Ambiguous Cylinders



Lecture 13. Ambiguous Tiling

   Comments on Lecture 13
   
Gallery of Ambiguous Tiling



Lecture 14. Triply Ambiguous Objects

   Comments on Lecture 14
   
Gallery of Triply Ambiguous Objects



Lecture 15. Ambiguous Objects with Six Interpretations

   Comments on Lecture 15
   
Gallery of Ambiguous Objects with Six Interpretations



Lecture 16. Impossible Motion

   Comments on Lecture 16
   
Gallery of Impossible Motion



Lecture 17. Figure Construction Methof for Ambiguous Objects

   Comments on Lecture 17



Lecture 18. Ambiguety with Shadows

   Comments on Lecture 18
   
Gallery of Ambiguety with Shadows



Lecture 19. Depth Reversal Illusion

   Comments on Lecture 19




Lecture 20. How to Draw Impossible Figures

   Comments on Lecture 20




Lecture 21. Pictures That Stand Up

   Comments on Lecture 21




Lecture 22. Viewpoint Trick

   Comments on Lecture 22




Lecture 23. Classical Illusion Caused by Depth Perception

   Comments on Lecture 23
   
Gallery of classical illusion caused by depth perception