#include <Wire.h>
#define pushPin 1
#define copyPin 0

void setup() {
  pinMode(pushPin,INPUT);
  pinMode(copyPin,OUTPUT);
  Wire.begin(8);                // join i2c bus with address #8
  Wire.onRequest(requestEvent); // register event
}

void loop() {
  delay(10);
}

// function that executes whenever data is requested by master
// this function is registered as an event, see setup()
void requestEvent() {
  char data=digitalRead(pushPin);
  Wire.write(data); 
  digitalWrite(copyPin,data);
  // as expected by master
}