So many solver solutions that day, either Z3 or Gauss-Jordan lol. I got a little obsessed about doing it without solvers or (god forbid) manually solving the system and eventually found a relatively simple way to find the intersection with just lines and planes:

1. Translate all hailstones and their velocities to a reference frame in which one stone is stationary at 0,0,0 (origin).
2. Take another arbitrary hailstone (A) and cross its (rereferenced) velocity and position vectors. This gives the normal vector of a plane containing the origin and the trajectory of A, both of which the thrown stone must intersect. So, the trajectory of the thrown stone lies in that plane somewhere.
3. Take two more arbitrary hailstones B and C and find the points and times that they intersect the plane. The thrown stone must strike B and C at those points, so those points are coordinates on the line representing the thrown stone. The velocity of the thrown stone is calculated by dividing the displacement between the two points by the difference of the time points of the intersections.
4. Use the velocity of the thrown stone and the time and position info the intersection of B or C to determine the position of the thrown stone at t = 0
5. Translate that position and velocity back to the original reference frame.

It’s a suboptimal solution in that it uses 4 hailstones instead of the theoretical minimum of 3, but was a lot easier to wrap my head around. Incidentally, it is not too hard to adapt the above algorithm to not need C (i.e., to use only 3 hailstones) by using line intersections. Such a solution is not much more complicated than what I gave and still has a simple geometric interpretation, but I’ll leave that as an exercise for the reader :)

Oh absolutely, I don’t blame KDE or arch repos lol. I did see that it was a KDE update but somehow didn’t clock the version number. I had it in my head that KDE6 was much farther off.

Didn’t realize this was happening and yay -Syu went brrr and it broke my shit. Probably doesn’t help that I’m running nvidia with linux (endeavouros). Wayland doesn’t work at all (black screen on login with only mouse ptr, wrong resolution), while Xorg is now much less smooth e.g. on the switching desktop animations. Moving windows around and in-window graphics are fine. Some graphical config stuff changed too; I’m still taking inventory.

I’m also currently playing with nvidia vs nvidia-dkms with different kernels to see if that solves anything.

EDIT: Looks like that my configuration was failing to set nvidia_drm modeset=1 correctly due to my unfamiliarity with dracut. Manually adding nvidia_drm.modeset=1 to my kernel cmdline makes Wayland work (and quite well at that), though Xorg is still laggy.

My condolences, buddy.

You may be interested to know that these kinds of paper adhesives are usually intentionally designed so that the substrate (paper) tears before the adhesive does. This is meant to ensure robust packing and to give proof that the package has not been tampered with. Couple this with ever thinner and shittier substrates, and, well…

Lol OW was the first thing I thought of.

Me: hey look a protan filter

OW: okay, red is now pink, and everything else is washed out :)

Me: okay tritan it is

OW: lol have fun on your acid trip