You need bigger walnuts, paper-clips and acrylic paint for the colouring.
We used a plain paper-clip, which we opened and bended in the middle. Thus you can insert the paper-clip into the walnut (there is a small hole at the one end). Insert it well to stay firm and not to slip.
We strung a felt-leaf on it.
It is easy to colour the walnut when you hold it by the paper-clip.