The present invention relates to a set (1) of plates (2, 3; 12, 13; 21, 22; 41) or parts obtained by cutting a block (4, 4″, 4′″, 35) of metal or composite material extending around a plane (5) comprising a first plate (2, 12, 21, 41) or part having an upper face (7, 33) and is second plate (3, 13, 22) or part having a lower face (8). The upper face (7, 33) of the first plate (2, 12, 21, 41) or part has a surface (7, 330) having at least two lines of inflection or changing slope with respect to said plane (5), and the lower face (8) of the second plate (3, 13, 22) or part has a surface (8) with a shape complementary to the upper face (7, 33) of the opposite first plate (2, 12, 21, 41) at a more or less constant height, corresponding to the height of the cutting line (34) in the block (4,35).