Show every item from the beginning to be examined

The Spike is examined by the audience

The blocks are examined by the audience

The bags are empty and can be examined by the audience before start

The participant can load the bags with the blocks and see inside of each bag to confirm everything is fair.

The participant can mix the bags

The participant can freely choose which bag you smash

After smashing the bags you can open them and show that only the blocks are found.