*this is not my cake*
How do I achieve this look. Looks marbelized, but it's so shaded I'm not sure. 
It is definitely marbled. To get this subtle effect, I would use four or five shades of the same color.
Color the fondant, or use already colored fondant. Roll each in to a log shape. Then twist and pull the colors together until you get the desired marble effect you're going for. I had a video, but it wouldn't link. There's good tutorials on YouTube.
Just remember when you twist those different shades together to just do it 2 or 3 times. It doesn't take much or you will end coloring the whole amount and not have the marble effect. You want to make lines of the color/paste/gel so you can have some of those dark streaks. When you have enough done for the upper tiers, then knead it a bit more to get it more solid as the bottom tier is. Here you might want to add a few more color streaks
Another thought. Maybe you could use a cloth (paper towel?) w/gel coloring on it and wipe it on the white fondant - after it is on the cake - or after it has been rolled out but not on the cake. Why not try both ways - on a small piece of fondant ahead of time - to see what give you what you are looking for.
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