Why it's shaped the way it is

The first stone nest was a sheet of paper on our living room floor. Lilly was lying on top of it, on her old bed, before it was anything more than a drawing.

The outline came from watching how dogs lie down. A dog circles first, turning a few times, then settles into a loose curl, nose toward tail. It's one of the oldest habits they have, and it's the shape we started from. That curl isn't a circle and it isn't a rectangle, so the bed isn't either. Its outline is rounded and a little uneven, the way a curled-up dog is.

Room for both

Then there's the other way dogs sleep. Lilly likes to stretch out, legs long, taking up as much room as she can. A rectangle makes you choose a size for one of those and live with it for the other. The uneven outline leaves room to curl up and room to stretch out, and your dog decides which, often both in the same afternoon.

Low, so it belongs in the room

We wanted Lilly's bed beside the sofa, where we spend our evenings, so it had to look like it belonged there. Tall bolsters make a bed look like a pet product from across the room, and they're something to climb over, which gets harder as a dog gets older. So the stone nest is low, with no raised sides and a soft, rounded edge your dog steps onto. It sits below the sight line of the rest of the room, so a dog lying on it can still see you, and you can still see them.

From across the room, the rounded outline looks like a smooth river stone. That's where the name comes from: the stone nest.

What the shape asks of the making

A rounded, uneven form is the harder way to make a bed. Each core is cut to its outline by machine, then the soft edge is built up by hand: a roll of foam is worked around the whole outline and glued in place. The liner and the cover are then cut and sewn to fit that outline, which curves differently at every point along its edge. It's slower work, and it's what gives the bed its soft lip instead of a cut face.

• The shape · The workshop · The studio.