This is one of Gann's trading method, called Price & Time Squared. When price & time meets, price will reverse."
as you see, those lines (past & future) represent the forecast of 'potential' swing (swing high/low or turning up/ down)
here are some examples:
Weekly
Daily
H1
M30
M15
M5
How to trade (very simple):
- if the trend is down and tomorrow there is a 'Price & Time Squared Line', we can prepare to take long position (combine with your favorite price action) - if the trend is up and tomorrow there is a 'Price & Time Squared Line', we can prepare to take short position (combine with your favorite price action) - stop loss if the chart makes Lower Low (for Long Position) - stop loss if the chart makes Higher High (for Short Position)
you can use those lines as guidance in your trading (just like Traffic Light)
PS: -if you see 2 or 3 lines close together, or 2 or 3 lines stack in 1 line (cluster), it means the Time Factor is 'Strong' the stronger the cluster the stronger the Time Factor - due to time delay & time lag, the turning can be +/- 1 bar - PM for trial access
“Time is the most important factor of all and not until sufficient time has expired does any big move start up or down. The time factor will overbalance both space and volume. When time is up, space movement will start and large volume will begin, either up or down.