The PhaserGames.com site has a new tutorial series on creating an Endless Runner game in Phaser: "Endless runner games have become a staple among mobile games. As a game developer, you may sooner or later be asked to make something similar. Working for years in game development, I often must start coding a game well before I have the graphics for it. While waiting for the artists to finish the cool art, I use temporary art. One artist, whom I worked with referred to this as “dev art”. The idea is to get moving on the code and replace it later with better stuff."