As you can see the similarity of movement between S&P 500 and 2008 crisis. It gives us helpful data for the forecasting of price movement. I made some adjustment on the length of 2008 pattern to simulate price movement.
I also made current situation comparisons with other past bear market ( dot-com bubble, 81-82 Recession, 77 Bear Market, 73-74 Oil Crisis, 69-70 Correlation)