1. Using the sellotape, re-close the open end of the empty cereal box. Cut off the back of the cereal box. This is your paint tray.
2. Place a piece of paper in the bottom of your paint tray (cereal box), you may need to cut the paper to fit if it is too big for the box.
3. Squirt some paint into the yoghurt pots and drop some marbles into the paint, swirl them round so that they get plenty of paint on them.
4. Drop onto the paper in the paint tray the marbles from one of the colours and move the tray around to make a pattern. Take them out and put them back in their colour then take the marbles from another colour and add to your picture.
5. Keep adding more marbles from different coloured paints until you are happy with your picture. Take the paper out of the tray and leave it to dry, then put in another piece of paper and make another marble picture.
6. You can paint on different coloured papers with as many colours as you like or use only one colour to make the picture you want. Here are some examples. The top right was done on black paper to look like fireworks. It might be a good one to try for Bonfire night!