Block Duplication glitch

Duplication glitch allowaws player to duplicate any block of their chioce.

1) in survival, choose block you wish to duplicate
2) place block
3) quickly hit the 'home' button
4) Double tap home button, and delete Minecraft PE from running apps.
5) Reopen Minecraft PE, and select your world.
6) the block you placed SHOULD be in both your inventory AND where you placed it.