* time, d_clk d_d_in
0n      0s 1s  
1n      1s 1s
2n      0s 0s
3n      1s 0s
4n      0s 1s
5n      1s 1s
6n      0s 0s
7n      1s 0s
8n      0s 1s
9n      1s 1s
10n     0s 0s
11n     1s 0s
12n     0s 1s
13n     1s 1s
14n     0s 0s
15n     1s 0s