An animation showing which notes are in a mode for a fixed root as the mode changes. The scale degrees are shown on the circle of fifths (left) and on a pitch wheel (right). The red arc on each shows which note is flattened as the mode changes.
The keyboard shows the root note (dark blue) and note to be flattened (red). As the mode changes from Locrian back to Lydian the root takes as half-step down.
Credits: Inspired by a discussion and animation by katch wreck on Mastodon and John Baez's posts about modes. I used the excellent two.js 2D drawing library to build help this.