How do you crochet a baby blanket that has two layers?

My friend has a baby blanket that has two layers of stitching to it. One layer is white and the other is multicolored pastels and there's a knotted fringe all the way around. The layers are worked around and through each other so there is no separation or gapping. My friend didn't make it herself and so can't geve me the pattern, and with all the poking and prodding and pushing and pulling I've done all I can figure out is it's some sort of V-stitch variation, but I've no clue how to work it. Does anyone out there know how to make this impossible-looking pattern?