By default, the announcement bar in Shopify's theme "Dawn" only allows you to specify text and a link, so this is an example of how to add a custom Liquid block. By being able to insert any HTML/CSS/Javascript/Liquid code, you can create highly expressive announcements.
An example of how to insert custom liquid code into the announcement bar of the theme "Dawn" to allow for free expression.
[Setting Method 1] Add a block type to the schema of the "announcement-bar.liquid" section
[Setting Method 2] Modify part of the code in the "announcement-bar.liquid" section (process to determine and display the block type)
[Setting Method 3] Add a custom Liquid type to the display block and insert any code
