Good continuation is one of the Gestalt principles of perception. Elements aligned in lines or curves are perceived as a group, and are considered more related than unaligned elements. For example, two V-shaped lines appearing side by side are perceived as two shapes. However, when those lines are inverted and connected at the bottom to form an X shape, we no longer see two V shapes but instead see one X shape. Good continuation is useful to indicate connectedness between or among elements.
Source: Universal Principles of Design: Good Continuation
Example 1 (original source) – Universal Principles of Design: Good Continuation
Example 2 (online source) – Continuity 
Example 2 (real life) – Poppy Monterey Pinot Noir 2014, Label
