Wednesday, November 30, 2011

Manual Exploits

One of the oldest traditions in video gaming culture is that of the manual exploit.

In a video game, an exploit means taking advantage of the system, for personal gain, in a way that the original programmers did not intend or foresee. Abusing a glitch or bug in the program to gain invincibility for your character would be one example.

A manual exploit, then, is taking advantage of a physical vulnerability in the system in ways that the programmers did not intend or foresee, often via a design flaw in the controller.

Perhaps the most famous example of a manual exploit from the old days is the "pencil trick" from "Track and Field."

"Track and Field" was an arcade game from the early 80s in which you competed in several simulated track and field events, such as the 100 meter dash, the javelin throw, and the high jump. Running in a race was accomplished via the use of two buttons - one for the left foot and one for the right foot.

It was important to push these buttons as rapidly as you could - but only in an alternating fashion. So a consistent rhythm was just as important as speed. Just as in a real race, where you need to put your left foot forward after your right foot, and your right foot forward after your left foot, the game would not advance your character along the track if you did something stupid like trying to move your left foot forward twice before moving your right foot.

Obviously, the faster you could push your consistent rhythm, and the longer you could maintain it, the sooner you would complete the race and the higher your score would be. If you were good enough, you might even get your initials in the high score board.

Gamers are a notoriously competitive lot, however, and the reward of having your initials at the top of high score board, for all challengers to see, was enough to motivate several devious gangsters into figuring out a way to game the system.

Hence, the "pencil trick" was born, which was described as follows by an old gamer:

"To prepare, take a pencil and thread it over your middle finger and under your index and ring fingers of your left hand. Place your middle finger between the left and right buttons, with the erase on the left button. Then, push down your ring finger, so it presses down on the button.

When you're ready to start, tap quickly with your right hand on the index finger side of the pencil, so that it pushes down on that right button. Continue to maintain pressure with your ring finger, so the pencil immediately presses back down on the left button."


In essence, a pencil is used as a see-saw between the buttons, pressing left and right, over and over, with your middle finger as the fulcrum. The result is an easily-maintained, yet lightning fast, perfect rhythm, which could never be achieved by two fingers alone. The player ends up with an incredible race time - and an equally incredible score.

More than one crafty gamer used such a manual exploit to guarantee their unbeatable high scores - and their initials - would remain indefinitely at the top of each "Track and Field" arcade cabinet in their hometowns. Of course, plenty of variations existed, as the technique was duplicated independently by multiple gamers all over the world - from a "spoon trick" to a "buzzsaw trick."

Well, I'm glad to see that the spirit of the manual exploit is alive and well in gamers today, as this clever gamer demonstrates a manual exploit in the very recently released "The Legend of Zelda: Skyward Sword:"



In this section of the game, your character is supposed to swing his sword left and right as quickly as he can, in order to try and chop the falling bamboo stalk into as many pieces as possible before it hits the ground. The sword's movement is controlled by the motion of the Wiimote controller, in a direct 1:1 correspondence. Swinging the controller left makes the the sword swing left, swinging right moves the sword to the right and - just as importantly - swinging up and down moves the sword vertically, meaning the sword can move at any angle and at any speed that the player wishes to.

Again, speed isn't the only factor - your ability to maintain a perfectly horizontal motion, back and forth, is also important, as swinging at an angle will push the falling bamboo off to the side, making it harder to score as many slices before the bamboo hits the ground.

Here, the gamer has tricked the Wiimote controller into thinking it's swinging back and forth in a blazingly fast, perfect motion, by attaching it to a spinning bicycle wheel. The details of why this trick works* isn't important - I just think it's cool that he was able to figure out how to use such a manual exploit.

I know I wouldn't have considered attaching my Wiimote to a bicycle wheel. But then, that's why I can barely manage chopping the bamboo into 30 slices, and he's almost reached 40!



* Footnote: If you're interested in the technical details of why it works, here's my theory: First, he calibrates the Wiimote into thinking that pointing straight upward is in fact pointing straight into the TV, which is simply a matter of telling the Wii that the default "Zero" position of the Wiimote is when it's pointing upward. Sort of like tricking your digital scale into printing out negative weights by "Zeroing" the scale when there's a weight sitting on it.

This way, the Wii thinks that you're swinging the Wiimote purely horizontally when in actuality you are swinging it in a purely vertical manner, and vice versa.

Then, the player spins the wheel. At first, the Wii senses that the Wiimote is moving in a direction away from the "Zero" position, in what it believes to be a horizontal direction, so it swings the sword to the right, at a speed corresponding to the speed of the wheel. The Wiimote keeps spinning around the wheel, but after it spins a little past halfway, it's now found itself in a position away from the "Zero" position in the opposite direction - so it instantly moves the sword back to the left of the default, ready to swing again to the right. The Wiimote keeps spinning, swinging the sword back to the right, before the sword flips back over to the left side as the halfway point is reached a second time. And so on. The result is that the sword keeps endlessly swinging to the right, with the Wii automatically resetting the sword so that it's to the left of the bamboo stick with every spin of the bicycle wheel.

So basically, the exploit relies on the fact that the Wii considers the position of the Wiimote, when it has been rotated 270 degrees away from the "Zero" position in a clockwise direction, to be equivalent to the position of the Wiimote when it has been rotated 90 degrees away from the "Zero" position in a counter-clockwise direction.

In other words, your character on the screen doesn't actually spin around with his sword, even though you're technically trying to tell the Wii that you keep swinging the sword around and around in circles - which would only be possible if your character
was swinging around in circles. Since the Wii can't reconcile these two facts, it just instantly moves the sword, and your character takes another swing at the bamboo.

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