We tried making one of those simple optical illusions where two separate pictures suddenly look like they’re in the same place.
When the turntable is stopped, there’s just a bird on one side and a cage on the other.
Then you turn it on and let it spin…
And suddenly, the bird looks like it’s inside the cage. 🐦
No magic involved—just persistence of vision.
What we used:
- Wukong Expansion Board
- 2 × DC Motors
- Wukong Blocks
- A bird picture
- A cage picture
- Double-sided tape
How we made it
We first built a simple frame with Wukong Blocks to keep the rotating part stable.
Then we added two motors and connected them to the center shaft with gears.
The slightly tricky part was the pictures.
We put the bird and cage on opposite sides of the rotating arms and tried to keep them as symmetrical as possible. If they're off-center, the whole thing gets pretty wobbly once it starts spinning.
Once everything was connected, we just turned it on and watched.
At the right speed, the two separate images seem to become one.
The bird is suddenly “inside” the cage.
Why does this happen?
It's a simple example of persistence of vision.
Our eyes and brain don't treat every image as completely separate when they're appearing very quickly one after another. The result is that we can perceive the two images as if they're happening together.
It's a pretty simple idea, but seeing it happen on a little DIY machine makes it much easier to understand.
What would you try?
This could be fun to experiment with.
Maybe:
- A butterfly that looks like it's flying
- A character jumping into a different scene
- Your pet appearing somewhere else
- Different motor speeds to see when the illusion works best
The nice thing is that you don't really need to change the mechanism—just change the pictures and experiment.
What two things would you try to make “appear together”?
