A Pattern is an item that is used in autocrafting. It stores the recipe that should be autocrafted.
Hold SHIFT to see the output of the Pattern displayed on the item texture.
The Pattern can be configured to be a oredict pattern.
When configured as a blocking mode pattern, this pattern will only allow to run autocrafting one-at-a-time.
Clearing a Pattern
Use SHIFT + right click in your inventory while holding the Pattern to clear it.