RectProps = ref object
  color*: Option[Color]
  radius*: Option[CornerRadius]
  stroke*: Option[Color]
  strokeWidth*: Option[float]

proc createRectangle(props: RectProps = RectProps();
                    elemProps: ElemProps = ElemProps();
                    children: seq[Element] = @[]): Element {...}{.raises: [],
    tags: [TimeEffect].}

proc fill(color: Color; elemProps: ElemProps = ElemProps()): Element {...}{.raises: [],
    tags: [TimeEffect].}

proc fill(color: Color; radius: CornerRadius): Element {...}{.raises: [], tags: [TimeEffect].}

proc border(strokeColor: Color; strokeWidth: Option[float] = none();
           radius: Option[CornerRadius] = none()): Element {...}{.raises: [],
    tags: [TimeEffect].}