%% PUT enough trend line$ on a chart\ may hit something barchart.com has a 32% buy on front month copper\which is a 68% sell. Metals dealers here have a 5 day wait on cash copper check, so avoids copper theft.
Every trend has a beginning, a middle, and an end. In the beginning there's not enough information to draw trend line. You need at least two peaks and two valleys to do that. In the middle there's a brief window where you have enough information to draw a trend line and you also have enough of the trend left to take a shot at it. At the end you have a solid trend line but sadly the trend is over and your bet is going to lose. So to answer the question, yes trend lines work. The problem is that the window of time in which they work is sometimes very small, and the amount of patience you have to exercise is extremely large.