module inc4 {
   input   in<4> ;
   output  out<4> ;
   instrin  do ;

   instruct do par {
      any {
         in == 0x0 : out = 0x1 ;
         in == 0x1 : out = 0x2 ;
         in == 0x2 : out = 0x3 ;
         in == 0x3 : out = 0x4 ;
         in == 0x4 : out = 0x5 ;
         in == 0x5 : out = 0x6 ;
         in == 0x6 : out = 0x7 ;
         in == 0x7 : out = 0x8 ;
         in == 0x8 : out = 0x9 ;
         in == 0x9 : out = 0xa ;
         in == 0xa : out = 0xb ;
         in == 0xb : out = 0xc ;
         in == 0xc : out = 0xd ;
         in == 0xd : out = 0xe ;
         in == 0xe : out = 0xf ;
         in == 0xf : out = 0x0 ;
         }
      }
   }