rectangle

Half the width. The height is fixed at 0.6 of the width, so the rectangle is 2×size wide and 1.2×size tall.

Colour.

Fill shape.

Draws the outline dashed — the shape that is not there: a construction, a ghost of a previous position, a region ruled out. As polygon's and segment's.

Opacity.

Text drawn beside the element — rich text, so $maths$ and inline formatting render. Fades and draws with the element.

Declared but not drawn. Animatable — hidden: true !cue.to{false}(at: 2) reveals it — and unlike a cue, a hidden element still frames the plot, so the axes do not jump when it appears.

Keeps the reader from editing this element on an editable: graph. Nothing at all on a graph that is not editable.

Text size.

Paint order among the marks: a higher layer is drawn later, on top; equal or omitted, the marks stack in document order (later on top). Written z: before the argand plane took that letter for its coordinate.

X coordinate.

Y coordinate.

On the argand plane, the position as one complex number — a complex expression: 3 + 2i, (3 + 2i)^2, sqrt(13) * e^(i * a), with i the unit and parameters read as complex. Instead of re/im.

On the argand plane, the real part of the position, a number; with im. z: gives both at once.

On the argand plane, the imaginary part of the position, a number; with re. z: gives both at once.

On the polar plane, the distance from the origin; with theta.

On the polar plane, the angle anticlockwise from the right, in radians — 60deg writes it in degrees; with r. On a categorical theta (theta format:), a name.