Looking through a kaleidoscope is fascinating. Making a homemade kaleidoscope is not that difficult. You can learn computational concepts while making one. Start the video and build your own version.
Computational Thinking Concepts: Sequences, Variables, Testing and Debugging
https://drive.google.com/file/d/1cDpDvXWpnxqC3D8UXIaHlVTWG2XZsVS2/view?usp=sharing
