The Microduck launch has distracted me from fixture drawings. I don't need it for work. I want a small learning project with a finish line, so 'learn robotics' is too vague. Would recognising one marker and responding to it be a sensible project to investigate? That's a capability I'd have to check, not something I'm assuming is supplied. Also, the $399 launch headline is not my delivered budget.
https://pollen-robotics.com/microduck/
I have almost the same marker idea. Before ordering, I'm looking at whether I enjoy working on the behaviour at all. The colour decision was considerably easier.
Check what observations and controls are actually exposed before fixing the project. A clear goal is good; the hardware still has to give you a way to attempt it.