Bokeh ("blur" in Japanese) is an effect that came from a happy accident. A lens out of focus captured the light of a candle which resulted in a blurred image with octagonal-shaped diamonds dots. The light painting in Lumiè also inspires in a similar way. The city lights and all night movement of these places will be part of your images. This app retails for $0.99/£0.69 and you can download it here.