(0.0.0) Proportional Sizes - JujuAdams/Bento GitHub Wiki

//Define our base box
box = bento_box_region(20, 20, room_width-20, room_height-20);
with(box) //Go into the scope of the box element
{
    //Create a child box that stretches across 90% of the parent
    with(bento_box("90%", "90%"))
    {
        //Position the rectangle at 5%,5% to centre the rectangle
        place("5%", "5%");
        style.fill.color = c_red; //Make this child red
    }
}