anchor.diff:        endmethod
         
         method Action setLeds(Bit#(8) v);
  -	 ledsReg <= v;
  +	 ledsReg <= pack(replicate(v[0]));
         endmethod
      endinterface
      interface LEDS leds;
  -      method Bit#(8) leds();
  +      method Bit#(LedsWidth) leds();
            return ledsReg;
         endmethod
      endinterface
  
positive.code: 
  import FIFO::*;
  import Leds::*;
  
  interface EchoIndication;
      method Action heard(Bit#(32) v);
  
negative.code: 
      FIFO#(Bit#(32)) delay <- mkSizedFIFO(8);
      FIFO#(EchoPair) delay2 <- mkSizedFIFO(8);
      Reg#(Bit#(LedsWidth)) ledsReg <- mkReg(0);
  
      rule heard;
          delay.deq;
  