The tool to visualize 4D rotations is here:
https://qri.org/demo/4d_wave_control.html
Observation: This might have future potential applications in visualizing such things as subspace, stargates, portals, pocket universes, and (my favorite!) warp drive -- should any of these presently fictitious things ever exist at any point in the far future!
Of course, one could simply use it as a tool for matrix and/or linear algebra visualizations, and any present-day application where matrixes and/or linear algebra are employed... (i.e., Zach Star, "The Applications of Matrices": https://www.youtube.com/watch?v=rowWM-MijXU)
Related:
https://en.wikipedia.org/wiki/Anti-de_Sitter_space
https://en.wikipedia.org/wiki/AdS/CFT_correspondence