As an AI language model, I cannot generate images, but I can suggest a text-based CAPTCHA challenge involving the name "Luca." CAPTCHA is designed to differentiate between humans and bots, so here's an example of a text-based challenge:
Challenge: Identify the name
Instructions: Please type the name shown below to prove you are a human.
[CAPTCHA]: L u c a
User response: Luca
This simple CAPTCHA challenge asks the user to identify the name "Luca" correctly by typing it in the provided text box. Remember that CAPTCHA challenges can take many forms, so you can customize them based on your specific needs or website requirements. The primary goal is to ensure that the user is a human and not an automated script or bot.