[Discuss-gnuradio] Nand D flipflop in gnuradio

Hi,

   Out of curiosity for implementing the digital circuits in gnuradio, I tried implementing nand D flipflop in gnuradio but stuck with it because gnuradio can't support loops.

I'm attaching grc file of what I tried. Can someone tell me how to make it work.

Thanks in advance

sandhya