Several hours into my tour of Casper Labs, I start to feel sleepy. Casper, the company famous for its internet-sold mattresses, set up this facility in San Francisco to test its products. There are levers that press down to measure the springiness of the mattresses' foam, wire coils that take the temperature beneath the wool-blend duvets, and many nice, pillowy things. Walls are padded with fabrics, each of them soft and inviting. A collection of jars contain down feathers, foam, curly wool.

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