Device for presenting (displaying) information with no harm to eyes even for children - the challenge itself.
Come up with a way to display information so that the eyes do not strain and do not get ill. It is a big problem today for about 500 million people, who intensively use smartphones and computers.
Providing such a device or method, children will be able to do computer games for many hours in a day without any harm to their health! That's what many of them really love to do.
This will allow all school subjects to be made in the form of computer games (including multiplayer!) as well as attention-catching videos to be produced by the best teachers, from whom children like to learn, no need to be forced! Choose the best: teachers, producers, actors, game authors. Games and the devices on which they are played should stimulate the whole body to be active. This will allow physical development, not only intellectual.
Then we can create an integral system of school education from A to Z without human teachers and visiting a school. Coupled with a system of distant and automated control and help to children, this will save a lot of money for school eduction.
As for social development, virtual reality (suppose, it will be safe for health, allowing to be in it all through the day) will give cheap or free opportunity to get social and communicational skills. Children may be trained both with human peers and by Artificial Intelligence playing for a peer.
For the first step: how to make electronic games to be fully safe for eyes even for children?