MIT (Massachusetts Institute of Technology) recently introduced the FlyFire project.
An image in space is created using miniature robot helicopters with multicolored LEDs.
These helicopters move anywhere in 3D space, then hover in mid-air to create the image of your choice.
Flyfire could involv
This is a companion discussion topic for the original entry at https://community.robotshop.com/blog/show/mits-flyfire-miniature-robots-create-a-3d-mobile-screen-in-space