i was messing around with pistons one day and discovered that you can duplicate blocks with gravity. curious, i started testing. this is the result.

This is a huge sand duplicator machine i made that duplicates sand using pistons when the lever is repeatedly pressed. this can produce over 1000 in less than 1 minute. the sand blocks can be replaced with gravel to get a sand and gravel duplicator :D

please note that this is my cration and should not be re-used without my consent.