Might as well
This is quite difficult to explain! My grammar book says:
"Might as well is used to compare one unpleasant situation with another."
So in this case: because he can't see anything outside the window, he could be looking at a painted board. It's a way of saying that you could be something - but you're not literally that thing.
"It's so dark, I can't see anything. I might as well be blind."
"He never talks to me. I might as well not exist."
It's also used in another way:
"I'll never win the race. I might as well not run."
"There's nothing on at the cinema. We might as well stay in."
I don't know if that helps. Perhaps somebody else can explain more effectively.
Rocking on the points
I imagine that he teacher is rocking back on his heels - leaning back and then forwards again. If the heels have been word down to wedges, the point would be the very back of the heel.
holes augured in it
I've never heard "augured" used in this way, and I can't find any definition that would fit. As you've probably found already, augur means to predict, so the use of the word here makes no sense.
Okay, found the explanation: auger --* Encyclopśdia Britannica
It's either a spelling mistake, or the author has confused the two words. If an auger is a drill, then conceivably the word could be used as a verb meaning to drill, although I can't find any dictionary that lists it as a verb.
Hey, I learned something! Thanks.