 Though the brackets only feature the seed numbers 1-16 in each region, the committee assembles an S-curve of teams seeded from 1 through 68.In theory, the teams 1-4 on the seed list will all be #1 seeds (the #1 "seed line"), 5-8 will be #2 seeds (the #2 seed line), and so on; however, bracketing rules often lead to some deviation from this.The S-curve is most important for keeping each region balanced, the ideal being that each region will be equally strong.