1. Pebbles on the beach or beside the river can be very colourful. Why don't you collect some to see how many different colours you can find?
2. Once you have found lots of different colours, why don't you arrange them in a pattern, or a circle or a square?
3. Why don't you look for special pebbles: ones that look like jewels, ones with lines running through them or ones that are the shape of a heart.