
SICP, On Second Thought - iamelgringo
http://prophipsi.blogspot.com/2008/02/sicp-on-second-thought.html
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mechanical_fish
_Second, SICP contains problems that are just plain busy work. Exercise 1.14
is a good example of this. I really don't want to draw on paper a huge tree
which represents the process generated by evaluating a procedure._

When I was a freshman in college I attempted to test out of first-year physics
so that I could get on with the second-year classes. I went into a private
meeting with the professor who was grading the tests.

"Well," said the professor, "you made some pretty silly mistakes here, and
here, and here. But I recognize the problem: you don't draw diagrams. Here,
for example, you made a silly mistake on this ladder-against-the-wall problem
because you didn't draw the balance-of-forces diagram."

I admitted that this was the case.

"You were a really strong high school physics student," said the prof, "so you
probably got used to being able to glance at problems and intuitively figure
out the answer in your head. But the procedure is important. You have to draw
these diagrams, and you have to make them correct. You will soon learn to draw
them very quickly, but you must learn to draw them, because there are harder
problems than the ones you did in high school, and you will find that you
can't always hold everything in your head."

And so I did.

I thought fondly of that professor a couple years ago when I first saw the
infamous airplane-on-a-conveyor-belt problem. I didn't find it that hard to
solve. I was taught by a master.

