What are the design challenges of creating stackable stone or concrete outdoor loungers?

Designing stackable stone or concrete outdoor loungers presents several unique challenges. First, durability is critical—these loungers must withstand weather conditions like rain, UV exposure, and temperature fluctuations without cracking or fading. Second, weight is a concern; while stone and concrete provide stability, they must be light enough for easy stacking and rearranging. Third, ergonomics play a key role—designers must balance aesthetics with comfort, ensuring the loungers are both stylish and functional. Additionally, surface texture must be slip-resistant for safety, especially in wet conditions. Finally, modularity is essential for stackability, requiring precise engineering to ensure stability when stacked and ease of use when separated. Overcoming these challenges ensures durable, practical, and visually appealing outdoor loungers.