What is this?

Very quick post here. A few days ago my family and I went to "Swiss Science Center Technorama" (kids always love it!). There are thousands of experiments to do and observe. Among other things, I found - this.

Who knows what this is? Those of you who read "The Senthien" will probably recognise it and know right away why was this interesting for me ;-) Unrelated to this post, I changed somewhat "The Senthien" book cover. In my pol, I had many who voted for that cover. My preference was the old one (just a tree), but perhaps this one might draw more attention from the potential readers, who knows? The cool thing about being a self-published author is that I can do that :) I can simply change things, and that‘s awesome! Have a great weekend, everyone!