Lily Pad

The Lily Pad is a collectable block found growing on water in swamp biomes. They can be walked on.

Placement
Lily Pads may only be placed on top of a spring or a flowing spring. Lily Pads occupy the block above water and are not part of the water block itself. There is also a bug with lily pads during placement. Sometimes when a lily pad is placed, it appears to duplicate itself to an adjacent block. However, when attempting to collect the second lily pad, it is destroyed.

Lily Pads face a consistent direction which depends on their location and is not affected by the direction the player is facing. Replacing a Lily Pad will not change the direction.

If a Lily Pad is placed by clicking on a water source block which has empty space (that is, neither another water source nor a solid block) below it, and the aim also hits a block, then the water source will be destroyed and the lily pad will drop as a resource.

Potential Uses
Lily Pads' primary use is for making paths over water without having to build bridges or use full blocks. This is very helpful for crossing oceans or rivers, and especially helpful for making farms, as you can now put the water needed to obtain wet farmland in the center of the farm, and still be able to easily access your crops without wading through water. Now that farmland is no longer trampled by walking or sprinting as of Minecraft 1.1.0, this method is much more applicable.

Lily Pads can also be used to create floating platforms, or waterborne bases in the ocean, as the player can place a lily pad on the water, then other blocks on the lily pad, rather than having to swim to the nearest landmass to create bridges.

It is possible to create an "instant island", by putting lava on a lily pad. The lava destroys the lily pad but forms a five meter radius disc of lava-covered stone in the water. Retrieving the lava may be possible from a boat; failing that, placing a block next to the island will help. If the player is in good condition and has armor, they can also just jump onto the lava, grab the source block, and jump off into the water. The flowing lava can then be quenched or waited out.

Lily Pads formerly served as a sort of mine in the water in SMP servers, due to them being rather difficult to see and boats breaking on harsh contact with them. This behavior was changed in Snapshot 12w21a as boats now break lily pads; on rare occasions lily pads can still break boats, but this does not happen consistently enough to make them useful as "mines".

History
Lily Pads were introduced in the Beta 1.9 pre-release. In Beta 1.9 Pre-releases 1-5, lily pads could only be placed on swamp water, and could not be walked on. Also when you destroyed the lily pad you could not place it. But as of Beta 1.9 Pre-release 6, lily pads are now solid. This means that all entities can interact with the lily pad block: arrows stick to it, mobs can walk on it, and boats can collide with it. Like the Torch, a Slab, or any other Non-Solid, it causes falling gravel and sand to become a drop. But the Player cannot swim through lily pads to the surface.

In Snapshot 12w21a boats no longer break when they collide with lily pads (usually -- on rare occasions, the boat may still break, but this seems random). Instead, the lily pad is destroyed, and may (50% chance) drop as an item.

Trivia

 * Lily pads are destroyed when the water beneath freezes.
 * Lily pads are destroyed when water flows on it. This can be used to climb by alternating the placement of lily pads and water source blocks without leaving the placed lily pads.
 * Even when swimming under water, lily pads can be destroyed with one hit.
 * When lily pads are placed on water source blocks that do not take up the space of the entire block (when the water is flowing to the block next to it), the lily pad will appear floating above the water source block.
 * In some lighting conditions, lily pads are less visible than other blocks when viewed from underwater.
 * Monsters cannot spawn on lily pads.
 * It is also possible for lily pads to generate on the surface of underground lakes.
 * When viewed from underneath, lily pads may be invisible.
 * If placed on the water in a farm, the water will still irrigate the nearby tilled land.
 * If a resource, such as Sugar Cane, is harvested next to it, the resource can land on it instead of sinking into the water, making it easier to collect.
 * Since Snapshot 12w27a a lily pad being hit by a boat at high speed will be harvested and can be collected as an item.
 * Placing a lily pad under another lily pad (beneath the water) will destroy both lily pads, and the source block the first one was on. More specifically:  The bottom lily pad replaces the water source block, destroying it.  The top lily pad is no longer on a source block, so it is destroyed.  The surrounding water blocks will flow toward and over the former source block, which destroys the bottom lily pad.
 * As with slabs, any block placed above a lily pad will appear to float above it. This is because even though the lily pad doesn't occupy its entire space, it still is a block, and no other block may occupy that space.
 * When placing a lily pad, the arm does not swing.