A Girl Scout sold over 5,000 boxes of cookies by leveraging Twilio's communication tools to manage incoming messages from customers and supporters. To achieve this goal, they used TwilioQuest to get started with Twilio, then implemented logic using the Twilio REST API, Studio, and Functions. They created a workflow that handled different types of messages, including cookie orders, donations, and general communications, allowing them to quickly respond to incoming messages while keeping their personal phone numbers private. Additionally, they used Twilio SendGrid to send emails to keep their wife informed about the sales progress without overwhelming her with SMS messages. The project was a success, not only for the Girl Scout but also for the developer, who earned a coveted Twilio track jacket and learned valuable skills in programmable SMS, voice, and email.