Chart patterns are visual representations of price movements that provide insights into future market trends. They are a cornerstone of technical analysis and help traders predict whether a market is likely to continue its current trend or reverse direction. Chart patterns fall into two main categories: reversal patterns and continuation patterns. 

Reversal patterns indicate that the current trend is likely to change direction. One of the most well-known reversal patterns is the head and shoulders pattern, which signals the end of an uptrend and the start of a downtrend. Its inverse, the inverse head and shoulders, indicates the reverse—a potential move from a downtrend to an uptrend. Another reversal pattern, the double top or double bottom, occurs when prices test a high or low level twice but fail to break through, signaling a trend reversal. 

Continuation patterns, on the other hand, suggest that the current trend will persist after a brief pause. Patterns like flags, pennants, and triangles are classic examples. These patterns typically form during periods of consolidation before the market breaks out in the direction of the original trend. For example, a bullish flag forms during an uptrend, suggesting that the upward movement will resume once the consolidation phase ends. 

These patterns can be used in conjunction with other technical tools, such as volume indicators or moving averages, to increase the probability of successful trades.