#include <Wire.h>

void setup() {
  Wire.begin();  
  Serial.begin(9600);
}

byte x = 0;

void loop() {
  Wire.beginTransmission(8); 
  Wire.write("value: ");       
  Wire.write(x);            
  Wire.endTransmission();    

  x++;
  delay(500);
  Wire.requestFrom(8, 8);     
  while (Wire.available()) {  
    char c = Wire.read(); 
    Serial.print(c);        
  }
  Serial.println();
  delay(100);
}