Assertion: rug's material | /r/ObjectUse | used for pile
Facets:
Source sentences:
text: A technical classification for Persian carpets is based on material used for warps, wefts, and pile, spinning and plying of the yarn, dyeing, weaving technique, and aspects of finishing including the ways how the sides (selvedges) and ends are reinforced against wear.
text: Polypropylene, a polyolefin stiffer than the cheaper polyethylene, is used to produce carpet yarns because it is still less expensive than the other materials used for carpets.
text: The most common materials used for the pile are wool, silk and cotton.