(i)-(iii) Siebeneck (Heptagon)

Imi Knoebel (b. 1940) (i)-(iii) Siebeneck (Heptagon) (i) signed and dated 'imi 75 86' and stamped with number '16' (on the reverse) (ii) signed and dated 'imi 75 87' and stamped with number '81' (on the reverse) (iii) signed and dated 'imi 75 87' and stamped with number '113' (on the reverse) each: acrylic on wood (i) 20 1/8 x 18 7/8 x 2 5/8in. (51 x 48 x 6.8cm.) (ii) 19 7/8 x 22 7/8 x 2 5/8in. (50.5 x 54 x 6.8cm.) (iii) 21 x 19 x 2 5/8in. (53.5 x 48.5 x 6.8cm.) (i) Painted in 1975-1986, this work is number sixteen from a series of one hundred and fifteen, each unique (ii) Painted in 1975-1987, this work is number eighty-one from a series of one hundred and fifteen, each unique (iii) Painted in 1975-1987, this work is number one hundred and thirteen from a series of one hundred and fifteen, each unique