Cut two identical squares from thick paper or thin cardboard
Fold one square in half and unfold it
Fold the top and bottom edges toward the center crease
Fold the left and right edges toward the center crease
Repeat with the second square
Place one folded square over the other at a right angle
Tuck each flap into the pockets of the other square
Press the edges firmly to lock the pieces together
Flatten and tighten the ddakji shape
Repeat with thicker paper if you want a sturdier ddakji