heart of glass

pretty, gorgeous, beautiful / clear, clean, pure / clean, not dirty / tidy, neat, everything put away / fair, impartial, of clear conscience

lip service; promising but empty talk / skillful completion of a task

a black-backed wagtail (Motacilla alba lugens)

pretty, beautiful

threatening sky, signs of rain, looking like rain / rainy weather

floral pattern

black-and-white tartan pattern

(mathematics) geometric patterns

(idiomatic) to keep a secret when asked about it, but let it slip inadvertently when chatting on another occasion