Figure 7: Four groups of sixteen 2D maps in the range of n=15, k=7, N ≅ 200 ~ 600, T=2700 ; (a) group (a1-a4) four MapV maps for the file left; (b) group (b1-b4) four MapV maps for the file right; (c) group (c1-c4) four MapV maps for the file 201-500; (d) group (d1-d4) four MapV maps for the file random_201-500.