If you can dream it, you can do it. (Walt Disney)
The reader might wonder: Why? What is this sleep communication good for? Admittedly, sending a simple random math problem into the dream of a sleeping person does not look like being of the utmost importance for mankind – honestly, at a first glance, it does not seem to be of any use at all. But if one sees this as a basis of other future technologies, this point of view might change. Some of these possible future technologies shall be described here briefly.