The line is made up of points that are represented in a polar way where the radius is the price of BTC on a logarithmic scale and the angle is the time where a full turn corresponds to 4 years, which is approximately when the halving occurs.
The green dots are the halving dates, the orange ones are the ATH (All Time History) of the cycle and the gray ones are the minimums.
Looking at the chart, you can see that there has been no line crossing, which means that the bitcoin price has never been lower than 4 years ago. It is also observed that to date the maximums (orange dots) and minimums have occurred in the same halvings.