The Thomas Crown Affair (Excerpt 1: opening title sequence) (QuickTime)
The Thomas Crown Affair (Excerpt 2: opening title sequence) (QuickTime)
The Thomas Crown Affair (Excerpt 3: polo scene) (QuickTime)
Pablo Ferro was in charge of the graphic design and optical effects in this 1968 original directed by Norman Jewison. Ferro uses a variety of techniques: forming a larger image out of smaller subimages, moving the subframes, changing the tint colors of the subframes, duplicating the same image within multiple subframes, and so on. The jazzy score by Michel Legrand goes hand in hand with the rhythmic visual editing.
Unlike Ferro's work here, many (most?) split-screen works rely on fixed subframes whose positions and sizes do not change frequently if at all. Not to say it's somehow inferior: it's just part of what makes them work or not - how our perception negotiates the combination of changing imagery within fixed subframes. Ferro, on the other hand, doesn't keep any of his visual elements still for long, and I love the resulting playfulness and lightness of touch. He makes it look easy.
You can find out more about Ferro at his official site. (I've removed the link as it is now pointing to a porn site.)