Price and Time squaring is the most used phrase when we talk about W. D. Gann.  Gann had a unique method of equating price and time and whenever in any given situation if price = time, where price = P x current vibration and time = T (days, weeks or months), it is considered as Price is Square with time. 

When Price = Time, it is imminent that there will be a change in short term trend or long term trend. The process is a bit confusing for many and hence there is an error in identifying the price and time square before it happens. Most of the analyst find it after the effect and justify why price and time has squared on a particular day. 

Few lines from W.D. Gann - Commodity Course :

"You will also find this helpful in connection with your Trend Line Indicator: By going over past records you will find that May Wheat makes many tops and bottoms on multiples of 12 and on one-fourth of 12 and one-half of 12. For example: 48, 54, 60, 66, 72, 78, 84, 90, 96, 102, 108, 114, 120, 126, 132, 138, 144, 150, 156, 162, 168, 174, 180, etc. Watch your daily highs and lows and when they hold for several days around an even price on multiples of 12 or the halfway points, you can buy or sell around these points with a stop loss order."

Now here is the problem with Gann, while writing about price and time he assumes that the reader is aware of the concepts and will be able to understand what he is writing. If you keep in mind that Price is Time and Time is Price then it will come to you naturally that there is a reference to both time and price at the same time. "on one-fourth of 12 and one-half of 12"  work in terms of time periods of 12 from a starting point.

Refer the chart above, if you notice Price and Time equated after 13 squares, for ease of identification the numbers are marked with "Orange Stars". There was a price turn at 6.5 squares as well, if you now go back to the statement above where there is a reference to one-half of 12 and multiples of 12, 6.5 x 2 = 13.  Hope many of you would have got the point above price and time squaring concept.