I have started programming app inventor apps. Some members of the Google app inventor group provide new insights. Here is one: The Google Charts API provides the tools to produce a growing variety of charts and maps to visualize data and share the results in web-based images. The tools are sufficiently flexible to support the creation of QR Codes.
and to the tools:
Use a QR Code scanner to test these codes.
I hadn't fully appreciated until I worked with this tool that the 'data' can be many forms (urls, app store links, phone numbers, poetry, mathematical equations, ...) and now under control of anyone who has a Google account. This capacity solves on of the outstanding questions that I had about the development of some ARIS Quests.