Alperovitz usually found out what was in each stack only when he read the news stories.
Each stack then has a pair of cheap glass lenses mounted over it.
"Look, it's all courtroom work," he says, pulling a file from each stack to show their similarities.
Around the sides and over the top of each stack are trees, flowers, rocks, water and grasses.
So the control systems on subsea B.O.P.s are far more elaborate and redundant, with two identical pods on each stack.
Whisk the vinaigrette well, and then spoon a couple of tablespoons onto each stack of roasted vegetables, making sure some chestnuts end up on top of each.
Take a handful of frisée, twist it in your palm to make a bundle, and set it gently on each stack of asparagus.
Now, in Paul's bedroom, Cavafy set up a bindery, with makeshift tables covered with stacks of folders, each stack a poem in all its versions over time.
After the guard placed it on the floor, they rushed forward and gathered around each stack of bread like animals at feeding time.
Stack alternating slices of turnip, beet and squash in the center of each of 6 serving plates, and arrange beans around each stack.
But if Subra had to sum up each stack in a single phrase, it might come down to this: public good versus toxic industry.
