Cambridge University has revealed how buttercups are able to shine a yellow light under our chins when a flowerhead is placed close to it. It's great that some of these old childhood games involving plants are still being discussed. Do children still make daisy chains? Do boys pelt each other with burdock burrs? Do bindweed flowers still get popped, conkers still get smashed and do girls pick petals off of anything to hand reciting 'he loves me, he loves me not'?