Next time you want to impress your buddies at the poker table, here's how to shuffle a deck with one hand. Or at least how I do it. This technique is slower than the familiar two handed flipping manuever, but it provides nearly as good a shuffle as far as actually randomizing the deck is concerned. With practice you should be able to pull it off every time.
Step 1: Hold the deck firmly between your thumb and first three fingers evenly spread along the top of the deck. I now notice that my first finger is in a sub-optimal position in the first photo there.
Step 2: Have your middle finger grab the top half and your first finger grab the bottom half and slide them apart. Using your 3rd finger as an anchor, move your middle finger up to the corner of the top half. Then rest the bottom half against your middle finger and slide your first finger down to about halfway along the edge.
Step 3: Put your ring finger along side the top half and slide your pinky next to your thumb. Your bottom three fingers should be able to get a firm grip on each side of the top half. Make sure your middle finger stays in the top corner.
Step 4: Use your pinky and thumb to pull the two halves completely apart.
Step 5: Plant your first finger about 1/3 of the way down the side of the top half, and use it as a fulcrum to leverage the bottom half into the side of the other half, and mesh the cards as even as possible. Really push with your thumb. If cards are getting stuck against each other, you can lift up subtly with your first finger to spread the top half slightly and make it easier for them to slide past each other.
Step 6: As soon as you get a bite in, move your thumb over to the side. The picture doesnt show it, but that was actually a really nice mesh, but it needs to be a smooth motion and I had to pause to take the picture and they began to slip. Which brings me to an important point. Remember the whole point of this exercise is to show off your manual dexterity and intimidate some profit from your amateur poker victims, thus either avoid sloppiness or don't bother.
Step 7: Pack the deck back into shape, and manuever it back to position 1. This is actually one of the harder parts to do quickly, and you will be highly tempted to use your other hand. Do not. As I said, that ruins the whole point. Practice until you can do the whole procedure relatively fast (under 10 seconds) and smooth 100% of the time before presenting. A variant of this can be used to simply cut the deck, which is much easier and you can really whip through the deck and look cool. If you recall the movie Lock Stock and Two Smoking Barrels, there is a scene early on when the gambler character is chilling with his eyes closed motoring through the deck w one hand. I am that good.