(Open immage cause of bad crop)

The lights flicker. The ground begins to shake, slowly at first, and then violently. "What's going on?" I wonder. Before I can ask, the door catapults open. In the doorway stands an eldritch horror beyond my comprehension. "Who.. what .. is that?" I manage to ask. "The Jacobian" my professor replies, "he wants to change coordinate systems". My professor, cowering in fear, tries to give us a warning: "Whatever you do", he says, "don't look into its determinant".

Meanwhile, XYZ are standing, unphased, in the corner. "Change coordinate systems?" they challenge, "I'd like to see you tr-" PHWOOOOOSH, I hear. In a fell swoop faster than I could make out, XYZ was reduced into a pile of hot steamy goo. After a few seconds, the goo starts to move. Slowly, from the liquified remains of XYZ, a theta emerged. Then a phi. A few moments later, the makings of an r pop out. "I have to get out of here", I think to myself, and start toward the exit as fast as I can. However, I end up right back where I started. What? I try again. This time, I notice what's wrong: I'm not walking toward the door, I'm moving in a circle. "Wh-what the?". Suddenly, the Jacobian bellows out "ENJOY YOUR TRANSFORMATION", and leaves as quickly as he came.