Brick Red and Cream Turkmen Gül Bokhara, Hand-Knotted Wool Rug

100% wool pile, hand-knotted, with a natural fringe at both ends. Wool is resilient and forgiving underfoot, which matters on a room rug of this size that will carry furniture as well as traffic.

A deep brick red ground hides everyday marks well, and with the field half covered in drawing there is little open ground for a mark to show against — a practical rug for a busy room. The cream is the vulnerable colour, and here it matters more than usual: it is half the surface, and it is what the whole figure-and-ground effect depends on.

Look at the field for a moment and it will change on you. Sometimes you see cream güls sitting on a red ground; sometimes you see red compartments held in a cream net. Both readings are available and neither wins, and there is a measurable reason for that: across the centre of the field the cream drawing covers fifty per cent of the surface and the red ground the other fifty. Sampled again a little further in, it comes out fifty-three to forty-seven. The two are balanced almost exactly.

That balance is what makes the effect possible. Figure and ground separate when one has clearly more surface than the other — a thin motif on an open field reads as a motif, and the eye never questions it. Take the two to parity and the distinction stops being obvious, so the eye keeps switching between them. It is the same principle behind the familiar vase-or-two-faces drawing. On a rug it means the design never quite settles, which is why something built from a simple repeated emblem stays interesting to look at over years rather than becoming wallpaper.