Function add_circle_quadrant 

pub fn add_circle_quadrant(
    path: &mut Vec<Pos2>,
    center: Pos2,
    radius: f32,
    quadrant: f32,
)

Add one quadrant of a circle

• quadrant 0: right bottom
• quadrant 1: left bottom
• quadrant 2: left top
• quadrant 3: right top