When Jacob and the Man in Black had grown up, the Man in Black left his brother and Mother to go live with a group of villagers living on the island whom had promised him a means of leaving. In an effort to fulfill that, he dug a well deep into the earth in an attempt to locate The Source. He then constructed a donkey wheel with which he explained would be an instrument in his exodus, "combining light and water". He was asked how he knew this, and he replied saying "because I'm special." His project was never completed by on-screen, as he was knocked unconscious by his mother and the well buried.
It is evident that the contraption was indeed completed as centuries later, Ben Linus would utilize the wheel to move the island in an effort to evade Charles Widmore's attempts at locating it. When the wheel is turned the light emanating from the source brightens eventually causing the entire island to be transported somewhere else. It is alleged that whomever physically turns the wheel is forever banished from the island. After Ben turns the wheel, it (unbeknownst to Ben) becomes dislodged, causing the island to skip through time. Locke is forced to fix the wheel, injuring himself in the process and subsequently teleporting him off-island to Tunisia.