This formula can be rewritten to calculate T(x,y,t) based on the temperature at the previous interval. The formula can be visualized as a stencil.
The blue dot signifies T(x,y,t), whereas the red dots signify values of T at the previous time stamp on which T at the current time step depends.
Stencil being one of the very popular parallel patterns, was a topic of Chapter 8 in "Programming Massively Parallel Processors" by David Kirk and Wen-mei Hwu which inspired me to use this visualization and apply the suggested optimization to parallel stencil.