Players can make Walda smile through certain passphrases. Although Walda's dad asks the player to tell him the secret words, the passphrases are actually strings of letters that vary on several components, chiefly the player's Trainer ID.
If a passphrase is valid and makes Walda smile and laugh, her dad rewards the player with a wallpaper for his Pokémon Storage System. The wallpaper's design is based on the other components that make up the passphrase, including the wallpaper's pattern, icon, and background and foreground colors. There are a total of 256 valid passphrases, each of which rewards the player with a different wallpaper. There are secret word generators available online that can quickly produce the passphrases.