#include <U8g2lib.h>
#include <Wire.h>

U8G2_SSD1306_128X64_NONAME_F_HW_I2C u8g2(U8G2_R0, U8X8_PIN_NONE);
volatile int item;

void left_open() {
  u8g2.drawRBox(15,(item - 1),30,(item - 1),3);
}

void right_open() {
  u8g2.drawRBox(75,(item - 1),30,(item - 1),3);
}

void right_close() {
  u8g2.drawLine(75,30,45,30);
  delay(1000);
}

void setup(){
  u8g2.setI2CAddress(0x3C*2);
  u8g2.begin();
  item = 0;
}

void loop(){
  randomSeed(millis());
  item = 20;

  u8g2.firstPage();
  do
  {
    left_open();
    right_open();
  }while(u8g2.nextPage());
  u8g2.firstPage();
  do
  {
    right_close();
  }while(u8g2.nextPage());
  if (item == 1) {
    item = 20;

  }

}