Initial comments

[kvid]

I like this sandbox to play with new ideas.

These are my initial comments during my first reading of the committed code:

misc.py#L2: Optional is not needed unless we need to allow None as a legal value.

misc.py#L16: Is ColorScheme a possible alternative name for this class? I believe I have seen the color code term also being used for the RGB or HSV values.

links.py: I suggest a new class to be used for each pair in the Connection and MatePin classes:

class EndPoint:
    id: Designator
    port: int

[17o2]

All sounds good. Any alternative to Endpoint, since it's also used in Connection to identify a cable the connection goes through, so strictly speaking it's not an endpoint?
In the meantime I've implemented it as you suggested (ace8ae9)

[kvid]

All sounds good. Any alternative to Endpoint, since it's also used in Connection to identify a cable the connection goes through, so strictly speaking it's not an endpoint?

I believe Connector.via will need a different type hint, specifying a leaf node in the hierarchical structure of a conductor, and maybe even where along the conductor length to create the connection (unless EndPoint is expaned or subclassed with an attribute for distance from conductor end = default zero).

In the meantime I've implemented it as you suggested (ace8ae9)

Both Connection.source and Connection.destination should have Optional[EndPoint] as type hint to support connections with one unconnected end.