How to set a input as fixed binary pattern?

If I understood you, you need to design a 16 bit shift register as above replacing 64 bits with 16 bits then kick it on every clock edge.

For changing value every 16 clock cycles then simply load new value into shift register. You will need a small counter say 0 ~ 3 to load a specific value at each count. if count 0 load x"...", else if count 1 load x"...." and so on.