The first one is part of the syntax for defining a sum type, the second is a function returning a tuple, and the third is a function returning a record.

I get that I just don’t understand why they chose to make them all so different.

Are you asking why different things look different?

Come on. I’m asking why they chose such different syntaxes for type annotations when it would not have been terribly challenging to keep them consistent. I even gave examples.

Parens vs curly braces. Single : vs double ::.

The first example isn't a type annotation, it's a type definition. The curly braces are consistent with the literal syntax for records. I agree that the use of double colons in record types seems inconsistent. I assume it resolves some ambiguity.

You are spot on. Its because we reserve `:` for type and kind ascriptions. For example, `42 : Int` or `true : Bool`. But we also have `Bool : Type`, i.e. `true : Bool : Type`. While kinds are not that common in every day code, we aim for consistency with ascriptions rather than with records. Hence we had to use a different symbol in record types.

> I even gave examples.

Yes, of different things that look different, then asked why.