Has Nifty already reached a high ?

It is observed over the historical data of nifty, if it makes a new high and corrects by 20% it reverses towards a breakout with previous 52 week high and creating a new high in over 12-18 Months. The rally is already at its peak of 18 Months.

What are your views on this theory. Do you think the rally would continue or the correction would pull the markets further down?