The design of the outer packaging of cola bottles involves artistic and functional considerations. It typically includes branding elements such as logos, colors, and graphics that are consistent with the product's brand identity. Functionally, the packaging should protect the contents, be easily recognizable, and facilitate handling and display. It may also incorporate sustainability factors, like using recyclable materials. The design process often involves market research, creative brainstorming, and prototyping to create an effective and visually appealing packaging solution.