In Finland, the ryijy is a traditional craft made from yarn. Basically it's a shag carpet!! These have been made in Finland for hundreds of years, and they use to be used in homes as textiles. Nowadays they are merily for decoration on the walls. They can be also quite expensive, hundreds of euros, because of the amount of time that it takes to do a large piece of art.
I had my class just try it out and practice the technique. I only required them to make a few lines with the yarn.
Then for our castles. We collected cereal boxes and toilet paper rolls for this project. It took us many weeks to accomplish. We also made a base for the castle from cardboard boxes (which I diligently cut in advance for the students). When it was all done, students then created characters for their castles. They enjoyed this project very much!