How does beaming notes help show rhythmic stress patterns?

In musical notation, beaming—the practice of linking successive notes together with a stroke—serves as a supplementary system for indicating rhythm and stress patterns.1

The primary implication of grouping notes under a beam is that the first note in the group carries a stress. By organizing notes in this manner, composers and engravers can achieve two main effects:1

• Reinforcement: Beaming can be used to visually align with the time signature, reinforcing the established metre of the piece.1
• Contradiction: Beaming can be used to intentionally contradict the metre, creating a cross rhythm that highlights a different stress pattern than what the time signature might otherwise suggest.1

While bar lines and time signatures provide the foundational framework for pulse and measure, beaming offers a flexible way to clarify or manipulate the rhythmic emphasis within those measures.1