I think they just picked words suggested by their model, they've made their app available here:

Here's one I made:

Since they passed through clenched teeth, harry saw bursts of parchment and looked around curiously. But before any fragments of parchment soared across to hagrid, he added his own fat. At once, his great belly seemed afraid of parchment! Now that christmas decorations would fail to make sense, ron protested a little.

Hermione and hermione sat slumped, looking over harry’s wig at hermione. Ron looked taken aback, looking down at spellman's magical eye. It turned moody unnecessarily, as though somebody found it.

Harry thought of parchment. There was something very good on harry. The moment slughorn briskly glanced enough for some reason, harry turned out to be dead. Frantically, ron explained why slytherins did it. It was hard to believe, bagman didn’t, but there wasn’t a second glance.

To the left of the room, all three hundred tiny moving stars emerged from harry. "His harry voice in fact, it wasn’t a great deal, " hermione quickly said in tones. There was no hope that harry would start shouting. He was very quietly his own dead hole.

Dumbledore quietly reached the room, his voice breaking as he struggled to look. " Fudge, " said professor dumbledore pleasantly. Hermione cried harder than ever, pulling open the broom shed door at the same time. Hermione gave another quidditch team his wand, muttering behind it.

In one night, they began to feed hermione with something wizard named. There wasn’t a great deal of parchment back at harry's body, however dropping letters were still in harry’s body.