Photoshop - scanning and editing

First, i have arranged my objects on the scanner to get the desired image and then scanned it in.

Next, i launched them in Photoshop in order to edit them:

1

• I have duplicated the "Background layer" to get the "Background - copy" layer.
• I have set the new layer to "Difference"
• To get the desired effect, i went to Image > Adjustment > Postersize and set the value to "4"
• As seen on the "1" print-screen, abnormalities appeared on the screen. I didnt expect it to happen, but i liked the effect.
• I have resized the "Background - copy" layer to exaggerate the "Difference" effect.
• I have adjusted the brightness of the background image in the Image menu.

This is the final effect: