setup_egg Function

    function setup_egg() result(array)
    !! setup an egg, with yolk, albumen and shell
        use sdfs, only : sdf, sphere, box, egg
        use sdfModifiers, only : onion, revolution
        use vector_class
        use opticalProperties

        type(sdf), allocatable :: array(:)
        type(box) :: bbox
        type(revolution), save :: albumen, rev1
        type(onion) :: shell
        type(sphere) :: yolk
        type(opticalProp_t) :: opt(4)
        type(egg), save :: egg_shell, egg_albumen

        real(kind=wp) :: r1, r2, h
        
        r1 = 3._wp
        r2 = 3._wp * sqrt(2._wp - sqrt(2._wp))
        h = r2
        
        !width = 42mm
        !height = 62mm

        !shell
        opt(1) = mono(100._wp, 10._wp, 0.0_wp, 1.37_wp)
        egg_shell = egg(r1, r2, h, opt(1), 2)
        rev1 = revolution(egg_shell, .2_wp)
        shell = onion(rev1, .2_wp)

        !albumen
        opt(2) = mono(1._wp, 0._wp, 0.0_wp, 1.37_wp)
        egg_albumen = egg(r1-.2_wp, r2, h, opt(2), 3)
        albumen = revolution(egg_albumen, .2_wp)

        !yolk
        opt(3) = mono(10._wp, 1._wp, 0.9_wp, 1.37_wp)
        yolk = sphere(1.5_wp, opt(3), 1)

        !bounding box
        opt(4) = mono(0._wp, 0._wp, 0.0_wp, 1._wp)
        bbox = box(vector(20.001_wp, 20.001_wp, 20.001_wp), opt(4), 4)
        
        allocate(array(4))
        
        array(1) = yolk
        array(2) = albumen
        array(3) = shell
        array(4) = bbox

    end function setup_egg