∇ Quantum Fluctuations have led us to a world where the fabric of space-time is torn apart, and the laws of physics are constantly shifting like the sands of the Desert of Madness.
∂t/∂x But don't worry, it's just a minor ∂t/∂x problem, easily solvable by a nice cup of tea and a good dose of ∂x/∂t.
∂²t/∂x² Or, you know, just ∂²t/∂x² and hope for the best, because let's face it, the math is just ∂²t/∂x².