Robert Ryman, well he made this painting "Twin" with paint, and probably a brush, though you can't always tell. He has a great knack for making something happen with, well, seemingly not much! It's like he’s challenging us to really *look*, you know? The paint is applied in these thin layers, almost like washes, letting the surface breathe. See how the light catches those subtle variations? It's all about the texture, the color, and how the paint sits on the surface. Take a look at the lower right corner, the paint seems to have gathered in a delicate, almost accidental way. It reminds me that making a painting is a process, a record of decisions, and that's where the excitement lies. Kind of like Agnes Martin, only without the lines... or maybe, here, the lack of lines becomes the line?