kivy/examples/kv/app_layout.kv

BoxLayout:
    Button:
        id: bswitch

    BoxLayout:

        orientation: 'vertical' if bswitch.state == 'down' else 'horizontal'

        Button:
            id: btn1
            text: 'Button 1'

        Button:
            text: btn1.state

        Button:
            text: 'Button 3'

        Button:
            text: 'Button 4'

        Button:
            text: 'Button 5'