This was actually kind of shocking. Normally I have a box of the things sitting in the basement. And not a small box - it's ranged anywhere from one of the ones you get when you buy 10 reams of paper, all the way up to moving boxes (as in, 3' x 3' x 2', full of finished hills).
So, I figured I ought to churn out some hills before I wrote anything about it, even though I probably have dozens of pics of hills on the computer already. Plus, I was going to be running a tourney in early April, so it was a good excuse to spend some evenings working on terrain.
But then, real life happened, and I wound up running my first tourney with mostly unfinished terrain. (Boo! Hiss! Bad Pressganger!) In fact, I haven't put up the pics yet in part because all that bare pink foam is kind of embarrassing.
Anyway. I don't have WIP pics. I don't bother to take them with my hills, because it is generally not worth it. They are basically cut pink insulation foam, typically 1" thick (although I have also used 1/2" and 3/4", which look better for 1:160 and 15mm scale, respectively), with either straight sides or a slight bevel. The bevel is a compromise - the straight sides are great when it comes to gaming - a model is either on the hill or off it, and you don't have the "Argh!! My Devastator just rolled down the hill and took out pSorscha and some Widowmakers!" problem. But the straight sides just look wrong. And slopes either don't work (ie, rolling jacks), or are fragile unless you base them on something a little more sturdy. But bevels work okay, more or less.
So, my finished hills generally look something like this:
These work fairly well, are reasonably sturdy, and I can churn out a bunch of them in an afternoon. Actually, that's not true - while it's not as though each hill is a finely made, bespoke craft item, they do take some time. But a lot of it is waiting for paint or glue to dry. I can cut a bunch of them in an hour or so, and flocking them does not take much time. Heck, each layer of paint is pretty quick - but the paint just has to dry before the next layer. So I will generally paint up a couple dozen of them at a time, and let them dry. When I have a bunch of them fully painted, I flock four or five a day until I start running low on painted hills, at which point I just go and cut a bunch more foam with my hot wire cutter.
And, while the pic above is of the straight-sided hills, they all stack fairly well, provided that I remember to cut hills beyond a fairly narrow range of dimensions.
So, that's how I make my hills. And yes, right now, that paper ream box is mostly full again. (I trade off terrain from time to time, which is one of the ways I make a dent in my omnibus wishlist. I am thinking of taking a bunch of stuff to GenCon to dump in one of the auctions - it's unlikely that I can make the trip pay for itself or anything, but selling a vanload of terrain would let me buy more minis.)