One of the values of patterns with charts isn’t just to observe when things are going right, but also to recognize when things are going wrong. I was reminded of this today since Alexion was bought (symbol ALXN). The “heads up” on this was actually weeks ago, when the descending trendline was broken. Here are some good examples of how pattern violation presaged from powerful bullish moves. For bears, the break was a time to get out; for bulls, it was a time to get in.