This is called Sekka shibori which is one of Itajime Shibori dye techniques. It's created by pleating, folding, clamping and dyeing the fabric. The fabric has to be folded and pressed neatly to create nice and precise patterns.
DIY Room Decor: Make Your Own Macrame Curtain A Beautiful Mess. Actually think a FL-beachy house would be perfect for something like this. And yes, Im one of those who grew up with marcameing parents and swore I would never own anything like it.