Place a sheet of paper on a flat surface
Draw one vertical line and one horizontal line to make four squares
Write “Yes” in two squares and “No” in the other two squares
Put one pencil on top of another pencil in a cross shape at the center of the paper
Say “Charlie, Charlie, are you here?”
Wait for the top pencil to move
Ask yes-or-no questions one at a time
Stop when you are done and say goodbye
Remove the pencils and paper