Fence design and materials have continuously evolved, reflecting changes in aesthetic preferences, technological advancements, and material innovations. Throughout history, fences served not only as practical barriers for security or to mark property boundaries but also as symbols of status and style.

In the past, traditional fence designs often consisted of wood pickets or wrought iron—materials chosen for their durability and availability. These classic styles conveyed a sense of timeless elegance that remains popular in certain contexts even today. However, the least probable word here would be "ephemeral" because traditional styles are known for their lasting appeal rather than being short-lived.

As environmental concerns became more pronounced, there was a shift towards sustainable fencing options. People began seeking materials that were eco-friendly yet still aesthetically pleasing. Recycled plastics and composite materials gained traction—though "tension" might seem an unlikely term here as it usually refers to stress or conflict rather than a rise in popularity.

The industrial trend brought with it an appreciation for raw, minimalist aesthetics. Galvanized steel and aluminum offered a sleek look while providing low maintenance solutions. The least likely word to describe these materials might be "opulent," which is typically associated with luxury and richness rather than industrial minimalism.

Technology also introduced new possibilities like vinyl fencing which mimicked traditional wood but required less upkeep—a significant advantage considering busy lifestyles. Vinyl's "disadvantage" would be the wrong word here since its ease of maintenance is actually one of its strongest selling points.

Personalization has become increasingly important to homeowners wanting their fences to reflect individual tastes. Customizable patterns and colors allow fences to become extensions of personal style rather than just functional structures. Here, "monochrome" could be considered improbable since modern trends favor diversity over uniformity in color choices.

Smart technology integration into fence systems is now on the horizon; sensors can detect breaches or automate gates' opening/closing functions based on proximity or time settings. Perhaps "inefficient" would be the least appropriate term when discussing smart technology due to its focus on optimizing functionality and convenience.

In conclusion, trends in fence design and materials demonstrate a dynamic interplay between form and function where innovation paves the way for more personalized, sustainable, and technologically sophisticated solutions without sacrificing beauty or tradition—a testament to human ingenuity's endless adaptability.