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Layout of tested specimens: a—felt, b—office carpet (wave pattern), c—leatherette, d—bubble relief styrofoam, e—cork, f—office carpet, g—polyurethane foam, h—carpet with short fibres, i—anti-slippery matt, j—soft foam with wave pattern, k—felt with pattern, l—spruce wood, m—sandpaper, n—wallpaper, o—buble foam, p—plush, q—fake grass, r—aluminum thermofoil.
