As observed, these similar pattern can be traded at the same time.
DIA and SPY etf's can relate to the e-minis of YM and ES.
Notice the similarity of the pattern, they are almost or exactly identical.
They move mostly at the same time.
Trading them together especially today in the e-minis can make you a nice return.
That's why it is better to trade the futures than the individual stocks due to number of instruments to be monitored.
Tracking just the YM, ES or the NQ is more advantageous than tracking hundreds or thousands of stocks.