Square

Property	Default	Meaning
border-radius	0	Scalar, { x, y } / [x, y] pair, or side/corner object

Square is a rectangle with an intrinsic 1:1 aspect and square drawing geometry. Setting just width or height normally determines the other dimension:

If an allocation is not square, Square draws the largest centered square that fits inside it. Its layout rectangle still has the allocated dimensions. This differs from Rect aspect={1}: Rect expresses an aspect preference but paints its entire final rectangle, even if that preference is overridden.

border-radius works as on Rect, relative to the drawn square's sides. Paint comes from the shared style. The natural fallback is 16 × 16px.

An intrinsic aspect is local to this leaf. A VStack containing a Square does not inherit a square aspect, infer a shared width from its total height, or automatically grow the Square. Give the stack a width or choose explicit child flex allocation when that relationship matters.

The example allocates a 2:1 rectangle to each shape at the offered width. Square remains square; Rect paints the full allocation. The enclosing Frames reveal the sizes.