Not one.
Amy Shackleton applies wet paint to a canvas and then elevates and turns it so that the paint runs in the direction that she wants. After many carefully staged pourings over one or two weeks, she's made a complete, coherent image. Her technique seems to work particularly well for nighttime scenes. You can view more images and a time-lapse video of Shackleton at work at the link.
Link | Artist's Website
No paint-brush?? Only pouring?? cool ..
with warm regards
Another Author
If you follow the link you'll see the paint is applied to a blank canvas. But then you find far to many people commenting on here who never bother to follow the link.
how hard is that to do?