#include <USIWire.h>
#include <SoftwareSerial.h>

const int rxPin = 1;
const int txPin = 2;

void setup() {
 Wire.begin();
 delay(100);
 pinMode (0, OUTPUT);
 digitalWrite(0, HIGH);
}
byte x = 0;
void loop() {
 Wire.beginTransmission(4); 
 Wire.write("x is ");        
 Wire.write(x);             
 Wire.endTransmission();    
 x=x+5;
 delay(50);
}