I was staring at a puddle as a gust of wind hit it, producing the following wave pattern ...
To my mind, the only way this could occur is if the gust of wind had a distinct leading edge, much like if i moved a match-stick through the water along the red line.
Here's a picture of the puddle ...
It approximates a trapezoid, whose longest side (adjacent to garden) is about 2.5m, its shortest side about 1m, and its height about 1.5m. I estimate its maximum depth at 1cm. I didn't give this detail before because I have witnessed the same phenomenon countless times in various puddles and bodies of water, but only when it's windy! I'm surprised no one else has seen this?!
There are no kink lines along the path of the wave - I've seen the same pattern form along multiple paths of different direction in the puddle above.
I think @HotLicks could be on the money here - a vortex of some description could possibly cause this, but the path always seems to be surprisingly straight - not something I'd expect from a turbulent gust of wind.
The puddle has only been on my roof for a day or two so whilst it could be some sort of aquatic creature, I think it's unlikely given the length of time it's been there.