This fun little physics demonstration has now been made as a 3D printing project.
The impossible Domino physics toy was invented by ViralVideoLab November 21th 2020 and consists of two 3d printed parts designed by ViralVideoLab. As soon as you nudge the first domino, it knocks over the second domino and then stands up again by itself. An example of how to save energy.
I saw someone do this with two of those wide, flat highlighters once.
Their STL files are paywalled, though.
Image: YouTube / ViralVideoLab