Winogradky column
The Joyful Microbe blog has created a wonderful Guide to Winogradsky columns which helps people build their own Winogradsky column and to track the colours and progress.
For projects like this, I like to make seamless patterns to display different types of bacteria. This allows for re-use for several purposes and makes it easy to modify the design.
Winogradsksy column - Joyful Microbe