Un-Playable Piano Prank

This is the perfect prank for your musical friends. Please vote! 

Check this one out too!https://www.instructables.com/id/Glue-Stick-Water-Prank/

Step 1: Gather Your Supplies.

1. An upright piano
2. Two small boards that will fit loosely between the hammers and strings of the piano (We don't want to break anything!)

Step 2: Open the Lid of the Piano.

Locate the strings and the hammers to find where to put the boards.

Step 3: Insert Boards.

Gently place the boards so that the hammers will be blocked from hitting the strings. 

Step 4: Close the Lid.

When your victim goes to play the piano, the boards keep the hammers from hitting the strings.