Any surface can become a chalkboard... making it easier to create and share content more broadly in a classroom or on portable materials
Chalkboard paint may not be easily available in developing contexts, but you can make your own. They mention an easy way to also make the paint magnetic!
Perhaps a business could be built upon making and selling this paint? Or perhaps this paint can be used with masonite or other portable board to create individual, reusable slates for kids? Desk surfaces? Display walls?