Reservoirology #4: the case of Richards 1d

This is the follow up of Reservoirology #3 post, where (there) I used  Petri nets to represent ordinary differential equations (ODEs). Here, instead, I try to use the same graphical formalism to represent Partial Differential Equations (PDEs), by extending a little the graphics.

Let's say that the number of specifications needed is larger here and, therefore, a lot of ancillary information has to be conveyed through Tables (and some interpretation). However, click on the figure above if you are curious to know more.