#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2);
 
void setup()
{
  lcd.init();
  lcd.clear();     
  lcd.backlight();
}

void loop()
{
  char line0[99];  
  char line1[99];  
  
  static int m=1;
  static int n=0;
  
  sprintf(line0,"variable = %d this is a long text.",m) ;
  sprintf(line1,"variable = %d this is a long text.",n) ;

  m=m+7;
  n=n+1;
  
  lcd.setCursor(0,0);   
  lcd.print(lineX(0,line0,100));  

  lcd.setCursor(0,1);   
  lcd.print(lineX(1,line1,500));  
}

String lineX(int g,char c[],unsigned long milliseconds)
{
  static int q[2][99];
  static int r[2]={-1,-1};
  
  static unsigned long time[2]={0,0};
  unsigned long mill = millis();
  if (time[g]==0){time[g]=mill;}
  
  int i,j,k;
  j = strlen(c);
  char d[j];
  
  if (r[g]!= j)
  {
    r[g]=j;
    for (i = 0; i < j; i++)
    {
      q[g][i]=i;
    }
    goto JUMP;
  }
   
  if (mill-time[g]< milliseconds){goto JUMP;}else{time[g]=mill;}
  
  for (i = 1; i < j; i++)
  {
    k=q[g][i-1];
    q[g][i-1]=q[g][i];
    q[g][i]=k;  
  }
  
  JUMP:
  for (i = 0; i < j; i++)
 {
    d[i] = c[q[g][i]];
  }
    
  return d;
}