Magnetic Shelf

My wife, who is a 1st grade teacher, asked me to design and make small magnetic shelves for her ‘reading board’.  A whiteboard designated for her featured books of the week/month.  It is a simplistic design that functions well.  The back side has a rectangular indention that a high-strength adhesive backed magnet will fit nicely into.  I bought standard finish magnets which work, but if i were to buy more, i would go with a rubber coated one or put something like a film over the magnet to help add friction to keep them from sliding when heavy objects are put on.