On this occasion I will give you some ideas, make furniture from recycled cardboard.
Overall could say that there are two ways to convert the cardboard into something solid enough to make it a piece of furniture that can be used without danger of breaking.
The first is to create an interlocking structure based on layers of cardboard, in which the interior of the hollow structure but is relatively stable enough to withstand a certain weight. It has the advantage of requiring fewer sheets of cardboard to create the furniture, but also has more work and can be somewhat more complicated to do.In the following tables and chairs you can see how they crisscross the sheets to make furniture using relatively little solid cardboard.