Freak out week

I had a nerdy geologist moment last night at dinner.  I had just sat down in the caf, soaking wet in my kit from the day's rainy road adventure, and picked up my fork to mix my taco salad.  I went to fold the bottom layer of chips into the rest of the glorious creation and the entire pile slid, in one piece, almost off my plate.  My first thought: Oh no, the confining stress on my taco salad is greater than the tensor that I have applied.  Sigma 1 is vertical preventing me from mixing my salad.

Here is the diagram:

And this week is my first hell week for the semester.  Fun...