As cardboard boxes are discarded as waste and available plenty, an idea passed in my brain to create something useful with it, then after some search in internet came up with an idea of creating this dual purpose cardboard furniture.

Supplies

waste cardboard boxes (i have used computer CPU boxes as they were strong and unique in size)

fevicol/strong glue

sharp knife/cardboard cutter

wooden scale/steel scale

weights (lots of books)

Step 1: Preparation of Strong Base

take the cardboard boxes and cut it into a rectangle shape (4.5 x 1.3 ft)
now mark the cardboard sheet and bend the sheet in a zigzag pattern as shown in the figure
the ending of the sheet also to be bent

Step 2: Joining the Sheets

paste the two sheets in a opposite pattern as shown in the picture and place the weights (books or anything available) on these and let them dry for few minutes (approx. 30 minutes)
then paste each of the pasted two cardboard sheets to each other to form a honeycomb like structure and let it dry for few more minutes
now a strong base has been created

Step 3: Flexible Base Usage As Sofa and As a Bed

take 3-4 cardboard sheets of size (4 x 1.3 ft) and paste them together and this becomes a strong platform that can be placed on the base which we have created first to use as a small sofa kind of furniture.
use this furniture when required or store it by compressing the base when not in use
make five cardboard sheets as above mentioned above
expand more the honeycomb structured base and place the five sheets of cardboard and now it can be used as a bed