From El Greco's compressed cosmos in late-sixteenth-century Toledo to Antoni Tàpies's matter paintings in late-twentieth-century Barcelona, ten Spanish painters built the visual vocabulary the rest of Europe and the Americas borrowed from. The decisions each one made, and the line between them.

On the back wall of Las Meninas there is a small mirror, and inside the mirror are two heads — the king and queen of Spain. They should not be there. The painting has been arguing about why they are for three hundred and seventy years.

The Western painting tradition has been sorting dogs by role since the late Middle Ages — lap dogs in the lady's chamber, hunting dogs at the hunt, studio dogs at the painter's feet, guard dogs at the gate. Six painted dog-roles, each matched to a specific household register and a specific wall placement. For the dog-loving home that wants the wall print to recognise what the household's dog actually does, not what its breed looks like.

Eight dogs hiding in famous Western paintings — Velázquez's enormous mastiff in Las Meninas, Goya's small head emerging from sand in the Black Paintings, Hogarth's pug, Manet's terrier, Stubbs's hounds, Renoir's boating dog, Whistler's chihuahua, Hopper's cape cod evening dog. For the dog-loving home that wants wall art that recognises the household's actual fifth-member.

A young princess, her maids, a dog, two dwarfs, and a painter in the corner with his back half-turned. Reading Velázquez's most quietly radical canvas — the figures, the mirror, and the question of who is actually being painted.