What is the ideal forehead shape/slope angle

[𝔒𝔯𝔟𝔦𝔱𝔞𝔩𝔠𝔢𝔩]

Obviously some more others but what foreheads are bad vs good.
And what is the maximum and minimum slope/curvature that is acceptable

 

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A forehead with a moderate backward slope of roughly 10–15° from vertical, a smooth gentle convex curvature, and a gradual transition from the brow ridge to the hairline is commonly regarded as aesthetically balanced.

Very upright foreheads (around 0–5°) can appear more juvenile and slopes beyond 20–25° may look overly prominent or disproportionately sloped depending on the rest of the face.