The prefix network shown in Figure 5.7 is not the only way to calculate all of the prefixes in logarithmic time. The Kogge-Stone network is another common prefix network that performs the same function using a different connection of black cells. Research Kogge-Stone adders and draw a schematic similar to Figure 5.7 showing the connection of black cells in a Kogge-Stone adder. 

15 14 13 12 11 10 8 7 2 14:13 12:11 10:9 8:7 6:5 4:3 2:1 0:-1 14:11 13:11 10:7 9:7 6:3 5:3 2:-1 1:-1 14:7 13:7 12:7 11:7 6:-1 5:-1 4:-1 3:-1 14:-1 13:-1 12:-1 11:-1 10:-19:-1 8:-1 7:-1 15 14 13 12 11 10 7 6 5. 4 3 2 Figure 5.7 16-bit prefix adder Legend A, B; PEk Pk-1: Gk Gk-1 G-1-1A, B; Pri G Pri S;