Not because it’s blue, but because it refuses to fade back. Hang it and a plain nursery wall suddenly has something to look at, with two little dog faces tucked into the clouds for anyone who looks twice. It holds a wall on its own above a cot, a changing unit or a low bookcase, and it gives a quiet hallway a lift too. Keep the things around it simple: pale wood, white paint, cotton bedding, a soft grey rug. Don’t crowd it with lots of busy pattern or bright primary-colour decals the sky needs room to read as a sky. Printed on premium fine-art paper, with framing in real wood if you want a crisper edge.