AWK-powered N-bit binary sequence generator
          valid N-bit values: [2, 4, 8, 16, 32, 64, 128, 256] 
 (QRY)  re-base
 (DIR)  reset
 (DIR)  <<=
             current N-bit base : 16
 (???) 
          0:  0000
          1:  0001
          2:  0010
          3:  0011
          4:  0100
          5:  0101
          6:  0110
          7:  0111
          8:  1000
          9:  1001
         10:  1010
         11:  1011
         12:  1100
         13:  1101
         14:  1110
         15:  1111