Henry Moore wrote, "The sculpture which moves me most is full-blooded and self-supporting, fully in the round, that is, its component forms are completely realised and work as masses in opposition, not being merely indicated by surface cutting in relief; it is not symmetrical, it is static and it is strong and vital, giving out something of the energy and power of great mountains. If a work of sculpture has its own life and form, it will be alive and expansive, seeming larger than the stone or wood from which it is carved. It should always give the impression, whether carved or modelled, of having grown organically, created by pressure from within."

"Standing Figure: Knife Edge, the Archer, erected in a public square in Toronto, Atom Piece, Nuclear Energy, and the Locking Piece in front of the main facade of the Banque Lambert, Brussels, are bursting with energy and vitality, they seem larger than their physical measurements, impelled to grow by an irresistible force within." (I. Jianou, Henry Moore)

"In these very productive years between 1961 and 1964, bones - thick ones and thin ones - inspired many of Moore's most interesting pieces, such as Standing Figure: Knife Edge; Large Torso: Arch; Knife Edge Two Piece; Nuclear Energy and Locking Piece. This last was an impressively tough and three-dimensional bronze, originally cast in 1962 at three feet six inches high, and it was not misnamed: the two parts have to be turned as well as lifted to be separated...On different occasions the sculptor has said it was inspired by two pebbles with which he was playing, and which seemed to fit and lock together, and by a sawn fragment of bones with a socket and joint found in the garden, a likelier explanation." (R. Berthoud, The Life of Henry Moore, London, 1987, pp. 307-8)