[hirsin]

From the article - There’s something delightful in perusing Medium this way: the awkwardness with which the modern retina pixels need to accommodate the blocky, jagged font

They're certainly talking about their own experience, obviously on a retina display, but they don't include a picture. Which in a very image-heavy article implies that anyone should be able to imagine what that looks like. I can't, because I've never used a rMBP.