Here is a 1-paragraph summary of the text: The article provides a step-by-step guide on how to create a Spark web application that can dial and receive phone calls using the Twilio Voice API. The application uses Java 8 and Apache Maven as its development tools, and requires a free Twilio account to function. The tutorial covers how to set up the project, install dependencies, write Java code, deploy the app to a reachable server or use Ngrok for localhost tunneling, and add features such as dialing outbound phone calls and handling inbound calls. With these steps, developers can create their own Spark web application that can make and receive phone calls using Twilio's Voice API.