It's also been a good year for American Tower ( AMT). Shares of the $28 billion communications infrastructure firm have rallied more than 18% since the first trading day in January. And, like with PPG, the technical pattern forming in shares right now points to even more upside. That's because AMT is forming an ascending triangle pattern. Put simply, the ascending triangle is a pattern that's formed by a horizontal resistance level to the upside and uptrending support below shares. As the stock bounces in between those two technical price levels, it's getting squeezed closer and closer to a breakout above that $73 resistance level. That's our buy signal. To be sure, the pattern in AMT isn't pretty. It's not exactly a textbook example of an ascending triangle. But what's more important is that the pattern is tradable. $73 is the price level that's acting as resistance in this setup. Once it gets broken, I'd recommend being a buyer. Until then, it makes more sense to sit on the sidelines.