These designs with stamps in all four corners and a centerpiece are the easiest for them to copy within ACL 4.0.
To capture their attention, stamps, inks, cards, water and paper towels must be in plain sight, within arm's reach. Do not expect them to get up and go to the sink to wash the stamps. A squeeze bottle of water, a shallow bowl, and paper towels are going to be difficult to control. Practice ahead of time.