The title of this work derives from a mathematical term for a form of curve that is dependent on another shape or curve. The location of a point on a taut string as it is either unwrapped from or wrapped around a curve is called an ‘involute of a curve’ and so the title implies a spiralling movement. Hepworth gave this title to several loosely related works, which are all pierced, ovoid forms. In 1946, she explained the appeal of the ovoid shape and its potential, stating: ‘I have always been interested in oval or ovoid shapes, the first carvings were simple realistic oval forms of the human head or of a bird. Gradually my interest grew in more abstract values – the weight, poise, and curvature of the ovoid as a basic form’.

In Involute (1956) and Involute II (1956) Hepworth extends the curve upwards at a greater angle, and in so doing increasingly opens the form to create wide apertures through which light can pass enabling more of the surrounding environment to become visible. Here, space is now inseparable from form. Although closely similar in shape, Involute II differentiates itself from Involute by its larger size and highly textured surface. There is a sense of movement in this piece, with the bronzes less contained and more dynamic than the earlier carvings and resembling a crashing wave or the roll of a hill more than a shell. Involute II echoes the three-foot tall Curved Form (Trevalgan) from the same year, which has a similar curved bottom and enveloping sides although lacking the turn inwards to form the complex curved enclosure we see here.

The lively surface and medium scale of Involute II prompt in the viewer an instinctive, active engagement. Indeed, in its composition the viewer is encouraged to observe the sculpture from multiple perspectives, to walk around it, to peer through its apertures and to touch its highly tactile, multi-faceted surfaces. Hepworth mused on the medium of sculpture in a 1972 interview when she observed how ‘every person looking at a sculpture should use his own body. You can’t look at sculpture if you are going to stand stiff as a ram rod and stare at it. With a sculpture you must walk around it, bend towards it, touch it, walk away from it’. In common with her contemporary, Henry Moore, the numerous openings of Involute II engender connections between the work and the surrounding landscape, a notion which is underscored by the biomorphic qualities of its form.