I haven't done it (only because I don't have hardwood), but I really like the look. I think it does add extra color and coziness. I think adding or removing could be a way to change things up for the seasons too. I normally see larger accent rugs over the neutral, but I think it can be done with smaller rugs too.

Love this house.

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I kind of like it, depending on the proportions and how well they go together. I have done it one room where the larger rug is very light (was from my MBR in my old house) and the smaller one is also pale colors but an intricate silk. I had no place to store either one and they were costly so it seemed the best solution.

I don't care much for the look as it usually is featured in fussy, over decorated rooms, the exception being small, thin, colorful prayer rugs or very old silk rugs displayed over a less patterned or solid, more substantial rug or coir underneath. It seems to me it would work only as a very specific answer to a particular room rather than as a general design strategy.