You need a user interface design for an therapeutic graffiti game. Basically the game will allow the users to virtually start and create their own art. so add features like "free draw", "tutorials", a way to save drawing and share drawing as well etc.
Using a graphics editor such as Photoshop or GIMP, your team should prepare mock-ups of at least three significant screens of your application (not login or language choice).
The main menu, a game level, and content screens are all good candidates for further development from your wireframes.
Think about how the UI facilitates dialog between the user and the application. Remember, "content is king". Use this assignment to establish a theme that supports an intuitive story about what your app does.
The UI should leverage graphical themes established by your mood board and storyboard, and that shares a graphical look and feel across screens that includes the typography, color palette, and other visual treatments, like borders, icons, etc. Use the wireframes to inform the scale and positioning of navigation elements, buttons, menus, controls, text, and media.
Unless your team has a specific screen resolution in mind, 1024 X 768 is a good default size for desktops, the web, and tablets.
Make sure the background of your app is an alpha channel, so that all graphics that are developed for the mock-up can be exported and composited in the Unity IDE.
Design your graphics and buttons so they can be exported as discrete .png files.