The learning environment must be equipped with accessible materials for the child to explore at all times. When they were younger, activities need to be closely supervised, especially those involving cutting. Now that they can use the scissors safely, we have designated areas for art supplies and stationary within reach.
We don't start with a specific theme but discuss what is to be done and what materials are required. Parental intervention is left to the minimum unless the child needs help in a specific area.
Yes, we keep a constant supplies of toilet rolls, tissue boxes and bottle caps. They are about the most versatile materials which can be used to make about anything the child can imagine.
When they were younger, I had to research on themes and simple instructions will be given. If the task is technically too challenging, they can follow standard "templates" and add colours and decorations to their creations.
The artwork are usually displayed for a period of time until a new piece takes over. Before they are thrown away due to limited storage space, we take photos to document the art pieces. The children enjoy looking through their archives of artwork. It is surprising how much they can remember about the process and the thoughts behind even if it was done sometime back.
Our children have started formal school with structured curriculum. Home activities are meant to supplement and enrich their learning experience. They can decide what they want to explore and learn in a relaxed environment, instilling independence as well as collaboration depending on the activities chosen. They learn to communicate their needs and ideas. They take ownership of what they have done and learned.