Copy a given AB pattern exactly, then create an original AB pattern.
Copying a pattern means making your own row that matches another row exactly.
Once you can copy a pattern, you are ready to invent your very own.
Mastery looks like: Child accurately copies a given AB pattern and independently creates an original AB pattern with a different pair of items.
Common stumbles: Child copies the colors used but not the order, so the pattern looks similar but does not actually repeat correctly.