In the world of wave phenomena, when you clap your hands and sound comes out or when you throw a pebble into a pond and it ripples, those waves move out in all directions. And then we have this question, why is it that what we observe looks like particles leaving tracks that look like trajectories, not big puffy waves moving out in all direction? Of course, you know, because the particles are interacting and de-cohearing and you're seeing part of the wave function. You can actually do a calculation that says if you have a spherically expanding wave function and you put it in something like a bubble chamber or a cloud chamber, right?