This isn't theoretical too, here's an actual user who opened an issue where their MWE was using quaternions: https://github.com/SciML/BoundaryValueDiffEq.jl/is

This isn't theoretical too, here's an actual user who opened an issue where their MWE was using quaternions: https://github.com/SciML/BoundaryValueDiffEq.jl/issues/52 https://github.com/SciML/BoundaryValueDiffEq.jl/issues/52 This is how I found out it worked in the differential equation solver: users were using it. The issue was unrelated (they didn't define enough boundary conditions), so it's quite cool that it was useful to someone. It turns out the quaternions have use cases in 3D rotations: https://en.wikipedia.org/wiki/Gimbal_lock https://en.wikipedia.org/wiki/Gimbal_lock which is where this all comes in. Anyways, it's always cool to learn from users what your own library supports! That's really a Julia treat.