Use crayons to color different spots of bright colors on some paper. Color over the area with a black crayon. Cut out a shape. Use the popsicle stick to scratch out the black and reveal the colors underneath. or hang
Centaurea cyanus 'Blue Boy' - Cornflower - can be bought in bunches of 50 stems - cost around max. I could put you in touch with some British flower growers - you may be able to negotiate prices yourself and want to use British grown?