curve around the bottom-left corner and a curve around the top-right corner (start the curve at center-left and draw to center-bottom; start the other curve at center-right and draw to center-top). you will do this on every card in the left column. on the right column, you will do the exact opposite. draw your curves around the top-left corner and bottom-right corner (start the curve at center-left, and draw to center-top; start the other curve at center-right and draw to center-bottom).
after you have completed this, you will need to create an arrow. you can just draw this on a little piece of paper, or you can cut out the shape 