An email conversation has prompted me to do something I've been meaning to do for some time.
The dogma of predestination is very delicate and difficult to get just right. A step too far in one direction, and you slide into Semi-Pelagianism. A step too far in the other direction, and you're into Calvinism. And even within the legitimate bounds of the Church's teaching, there are various swamps, thickets, and blind canyons.
I've come up with what I believe is an original contribution to the question: a simple, easily remembered pictorial representation of the various schools of thought on predestination, in the form of a Venn diagram.
Visualizing the Dogma of Predestination
I don't have time to post the key right now -- which, if you've done any reading at all on the subject, should be relatively self-evident -- but I wanted to put up the drawing itself while I was thinking of it.