board buisness calendar dry erase dry erase board meet meeting office organization Organize plan planning strategy structure correction corrector deletion eraser erasing errors item marks mistakes object paper pencil pencil marks removal removing pencil marks rubber rubbery school stationery business empty letter lines message note old reminder study education vector write writing yellow circle construction draw drawing geometry homework project sharpener toools workplace clean dry erase fresh green hand start white whiteboard wipe blank illustration notebook page pen red sheet space text do don't forget instruction memory not prompt