Synopsis The fixed aspect ratio of a figure.
Function
FProperty onClick(void() handler)
Description Defines the ratio between the horizontal and vertical size of a figure.
This ratio is maintained whenever the figure is resized.
An aspect ratio with value 1, turns boxes into squares and ellipses into circles.
Examples 
e1 = ellipse(shrink(0.8),fillColor("yellow"));
b1 = box(e1,fillColor("red"));
render(e1);
e1 = ellipse(shrink(0.8), aspectRatio(1.0),fillColor("yellow"));
b1 = box(e1,fillColor("red"));
render(e1);
e1 = ellipse(shrink(0.8), aspectRatio(0.5),fillColor("yellow"));
b1 = box(e1,fillColor("red"));
render(e1);