Thank you for your question, this idea seems very novel and creative and not something we have really seen before! There are just a few issues that will occur when trying to progress in the creation of the tracking image in this way.
To start with, the complexity of the tracking image is not best practice and even with all four images superimposed we still wouldn’t advise to use it. The best tracking images are ones with a good amount of high contrast detail across the image. Images that are too simple or unbalanced may not track as well. Where possible avoid the use of repetitive high contrast patterns. The more diverse the areas of the image are, the better the tracking will be. Using your tracking image as an example - it is relatively simple with repetitive patterns meaning it is not following our guidelines for a ’What makes a good tracking image’.
You also have found out that only a portion of a tracking image needs to be visible for the ‘seen’ state to be activated (actions triggered). Our system tries it’s best to track to an image even if not all of it is in view, it seems as though even with the single image our system automatically recognizes this as the target and initiates the experience.
What we suggest is that you add some complexity to the tracking image (colors and background wouldn’t hurt) and keep testing to see if you can get this idea to work how you expected. Furthermore, you could ask the players to only scan the zapcode when they have all four images in place, removing the issue of the single image tracking the experience.
Please post the finished project on the show and tell page as we are excited to see how this ends up.
Hope this helps,