This is a post that I'm sure I will revisit in the next few years and say, "why didn't I just do ____! It was so clear!"
Major market reversal points typically happen at a multiples of 90°. Thus, all lines on the charts below are increments of 90° (unless noted). Let's take a look at the past 20-30 years of the major indexes. (None of these lines were manually placed at support/resistance areas. Instead, these lines are calculated using a single number at a major low pivot and the market followed them!)
Monthly Dow Jones chart, measured from the bottom of the '87 crash. I wish I had more historical data to do a complete analysis.

Monthly S&P chart, measured from the lowest low I have data for. The pop up and fall back to the 90° line is the '87 crash. Then a rally up to the tech bubble and financial bubble double tops. Both right on the 540° level (360°+180°=540°).

Monthly Dow Jones Transportation Average. I took the measurment from the '90 low, since it seemed to fit the data better. Since, the DJTA leads the Dow, perhaps if we see a bounce off 1959 area (90°) the overall market may be hitting a bottom. Perhaps the Dow will hit 5158 and S&P will hit 610 soon after the DJTA hits that area and it will start giving us a nice bottom.
Monthly Nasdaq 100, measured from the lowest point I have data for. I added the 300° line (270+30=300), since the 270 didn't seem to capture the reversal. Otherwise, the major reversals seem to happen from multiples of 90°.

Monthly bond chart showing the crazy bull move we've had the last couple months. We have never seen these highs before and never had this rate of ascent.
Lesson