How to Make a Sand Generator

Say you need some sand or gravel, but making the trek to find some is too dangerous or time consuming. Thanks to a piston duplication bug, you can have all the sand or gravel you want any time.

Place two water sources and surround the length of the water with blocks.

Make the outside edges 3 blocks high.

Place sticky pistons facing downwards along the walls.

Place sand or gravel below the pistons.

Place a lever at the front and run redstone wiring to the top of the structure.

Place the redstone on the two blocks between the pistons.

Hold right-click down on the lever and machine will sporadically spit out sand or gravel.

Within 10 seconds or so, you'll have stacks of blocks at your disposal.