A purple-blue lost dog poster can be a useful tool in helping to find a lost pet. The poster can be hung up around the neighborhood where the dog was last seen, giving people a visual reference of what the dog looks like and what to do if they spot it. The poster can also include contact information for the dog's owner, allowing people to reach out if they have any information. Additionally, the poster can be shared on social media, spreading the word even further. Ultimately, the goal of the poster is to increase awareness and involvement in the search for the missing dog, increasing the chances of a happy reunion.