In sight, in mind
In sight, in mind is a correlative to the axiom out of sight, out of mind. Meaning that if something is placed where it will be seen often, it will work as a reminder.
Implements in sight
This concept is the reason behind displaying a corporal punishment implement in a prominent location as a reminder to behave. Examples include: hanging a cane next to a classroom's blackboard, hanging a personal paddle on a bedroom wall, or a family's implement on a kitchen or playroom wall. Teachers who used a cane as a blackboard pointer have also profited from the effect.
This works best with dedicated punishment implements, whose sole purpose is chastisement, even if they are a pervertible set aside for such a task. A dedicated pervertible implement might actually be seen as an advantage to those of the praise in public, chastise in private belief as you would need to be "in the know" for it to be a reminder to behave.
A birch keeping in plain sight in the family room
Kitchen implements on a wall rack - the wooden spoon always in quick reach
Rules in sight
Pictures in sight
In spanking art and spanking stories (and probably also in some homes of spanko couples, couples under a domestic discipline plan, and those in a Taken In Hand relationship), pictures of spanking art are sometimes hung on the walls of the room or building of the setting. Besides their decorative function, these too can serve as useful reminders of what happens to those who misbehave.