dry stamp/linocut/paper, e.a., wymiary: 10,1 x 6,8 (printed area) signed, dated and described with a pencil at the bottom: ‘1976 „Monostruktury-próba” e.a. J. Grabowski’. dry stamp/linocut/paper, ed. 23/35, wymiary: 10,8 x 7,8 (printed area) signed, dated and described with a pencil at the bottom: ‘1979 „Dwie struktury z przekątną” 23/35 J. Grabowski’. dry stamp/linocut/paper, ed. 23/35, wymiary: 11,9 x 8,9 (printed area) signed, dated and described with a pencil at the bottom: ‘1979 „Struktura otwarta kodu” 23/35 J. Grabowski, imp.’. dry stamp/linocut/paper, ed. 9/21 II, wymiary: 12,4 x 9,9 (printed area), signed, dated and described with a pencil at the bottom: ‘1976 „Struktura monotoniczna I” 9/21 II .J. Grabowski’