Every good project I had started with taking a moment to consider the requirements.
I know it's not the most riveting content, but it will help to set the stage for later decisions

My usual approach is to identify the stakeholders and think about how they would interact with the device.

The main stakeholder is the person who would own this device, so let's start with that one.

The user would operate, observe, update, and touch the device.

The operation can be broken down into 3 other use cases:

• Starting up
• Shutting down
• Cycling operation mode

Next, we can assign requirements to the use cases.

Starting with the Observe use case, the high-level requirements are:

The visual intent of this project is to have a silhouette similar to this shape:

There are 4 Main operating modes:

• Keep at center
• Circle slowly (20 deg/sec)
• Circle rapidly (200 deg/sec)
• Trace a triangle

The user can cycle these operating modes by pressing the button on the device.

To start/shut it down, the user must long press the button. 

When the device finishes the start-up procedure it shall visually signal it to the user.
When the device receives a shutdown command it shall safely discard the ball from the plate if it's present. Otherwise, it would just roll off from the plate.

Let me know if you prefer more architecture building logs or want me to jump into the hardware build.