At this year's Frieze Masters art fair in London, Entwistle showcased one of the great masks in the opus of African art...
In a year in which both London and Paris saw major exhibitions dedicated to the genius of Picasso - 'Picasso 1932: Love Fame Tragedy' at Tate Modern in London and 'Picasso. Blue and Rose' at the Musée d'Orsay in Paris - it seemed almost by destiny that Entwistle exhibited the renowned and extensively published Grebo-Krou mask from Ivory Coast once in collection of Picasso's dealer, Daniel-Henry Kahnweiler [1884-1979] - see supplementary image.
With its remarkable geometric volumes and stark expressive energy, it was unavoidable that, after seeing this mask in Kahnweiler's apartment, Picasso would go on to own two Grebo masks of his own and, inspired by the dynamic balance of vertical and horizontal as well as projecting/recessed planes of these masks, he would go on to produce the iconic modernist sculpture 'Guitar' (1912), now in the Museum of Modern Art, New York.
According to the scholar Michael C. FitzGerald, “Picasso praised the reductive geometry characteristic of Krou (Grebo) masks, but he was particularly struck by the rendering of eyes as protruding cylinders, rather than as the deep hollows he had been taught to model in clay or plaster. This reversal of perceived ‘mass’ and ‘void’ inspired the crucial device of his Guitar, the rendering of the instrument’s sound hole as a hollow cylinder.
This conceit enabled Picasso to create an immediately recognizable sign and, at the same time, radically restructure an actual guitar by removing most of the top plane of its sound box. With the resonating chamber of the guitar open, the sound hole becomes the tangible centre of a highly synthetic composition of metal sheets.” 
The mask is a revolutionary platform for geometric dynamics as numerous planes intersect across its three-dimensionality, pushing the boundaries of depth perception and challenging the precepts of anthropomorphic portraiture; the mask never stops moving or speaking as it engages with the viewer.
The mask manages to express its power on so many planes that it almost becomes a lesson in the mechanics of equilibrium and three-dimensionality: the way the elongated forehead is bisected vertically by a raised median ridge, which then aligns perfectly with the sharp nasal ridge below; the forehead, as a semi-oval section placed on the top edge of the lower section so that the lower edge of the upper section becomes a deeply indented horizontal brow; the dramatically protruding cylindrical eyes that flank the high-set nasal structure and, below them, the mouth set as a rectangular block on the flat surface of the face and, producing further abstract inventiveness and surrealistic dynamic, a small metal chain is placed from both upper corners of the mouth to span rope-like across the frontal rows of kaolin-pigmented teeth..
On top of these architectural features, the colour schematic of the facial pigmentation is a wonder of abstracted design, at once controlled and radiating outwards to the perimeter of the face but also displaying a semi-expressionistic freedom of line and colour that carries beyond the physical frame of the mask - we observe the electric blue of the facial plane starkly punctuated by elements of white kaolin such as the slightly indented front edge of the eyes, where the the proper right eye is completely pigmented while the left is decorated with kaolin in ‘X’ form.
Commenting on this mask on its appearance at the seminal 1987 exhibition at MOMA, New York, William Rubin, its former Director of Painting and Sculpture, commented, "It is one of the few cases where we know that the contemplation of a tribal object directly influenced a major modern artist in a way that the artist himself was conscious of and spoke about. I think this is a very interesting mask. The notion of the eye as a cylinder is what interested Picasso. But that is true of all Grebo masks. What makes one better than another is everything else. And this [the present mask] is a good one, a very good one." 
 Michael Fitzgerald, ‘A Note on Western Artists’ Response to African Art’, in: Sotheby’s New York, The Saul & Marsha Stanoff Collection, May 17, 2007, p. 39
 William Rubin, ‘Grebo Mask’, in: Susan Vogel (ed), Perspectives: Angles on African Art, New York, 1987, p. 61