But, as it is the prompt for this week, I have gone with fast as in 'not slow'.
This is not a very good picture - but it should give you the idea. The small honey coloured blob is a very fast moving tiny dog - when I walk her for Mum I let her off her lead when we are within sight of the car. This is how quickly she moves when she is heading back to 'Mother' who has the car door open ready for her to leap in. I actually had the camera ready in one hand as I slipped her lead with the other - but she still got this far away before I had her in the picture and clicked!
This is what she actualy looks like - she is a long-haired chihuahua -