Beforehand I had drawn and cut out a tree shape out of brown paper and drawn lots of different sized circles on a variety of coloured papers.
Miss E choose a background colour and stuck the tree trunk shape onto it. She then cut out the different sized circles. With older children they can draw and cut out the circles themselves but drawing around things without them moving is still a bit tricky when you are 4!
We then experimented by layering up different combinations of colours until she was happy with them and then she stuck them together and then stuck the circle "sandwiches" onto the tree branches.
For older children they can do the activity themselves from start to finish including using a set of compasses if you are feeling brave!