In this video from American Society for Microbiology, you can get a look at some really incredibly artwork created by using agar plates, on which bacteria grow, and even learn how to create it yourself. The video features New England Biolabs Staff Scientist Mehmet Berkmen, PhD and mixed media artist Maria Peñil Cobo, who won the 2015 Agar Art competition for their work, shown in the first few seconds of the video.
They demonstrate their techniques, first by preparing the agar plates (the recipe is shown) which many people with experience working in the lab will already know about. After the agar plates are set, time to make the art. There are many colorful bacteria that are commercially available, but there are also a few strains that naturally make vivid colors. Berkmen and Cobo have access to many resources of course, which allows them to create complex agar art with a lot of features. But it's also possible to create some artful plates with only a strain or two, especially if you know a lot about the growing patterns of the bacteria you use; it helps for example, to know how fast the bacteria you use grows, especially if your plate has more than one bacterium growing on it.
They also have a some great pointers for capturing nice images of the agar art. Finally, there is a way to find out more information about how to submit your own agar art to the 2017 contest.