Note: while other reference pages inhibit the local saving of state, this page does save state so that the data-puzzle-id behavior can be observed. After state is saved, look for “reference-subgrid-example” in localStorage (often seen in the Application tab of your browser’s developer mode)
A puzzle may contain any number of subgrids. All subgrids share the same undo context.
Subgrids inherit the options set on the parent; any options specified on the subgrid itself override the option of the parent. The one exception: If a subgrid does not specify a data-puzzle-id of its own, it will be autogenerated based on the data-puzzle-id of the parent and the index of the subgrid.
If a parent puzzle contains subgrids, then no grid will be created for the parent itself.