main.py

from kivy.app import App
from kivy.uix.widget import Widget
from kivy.uix.scatter import Scatter
from kivy.core.window import Window
from kivy.uix.floatlayout import FloatLayout
Window.clearcolor = (1, 1, 1, 1)

class TextSquare(Widget):
    pass
    
class ScatterTestApp(App):
    def build(self):
        f = FloatLayout()
        scatter = Scatter(do_rotation=False,do_scale=False)
        scatter.add_widget(TextSquare())
        f.add_widget(scatter)
        return f


if __name__ == '__main__':
    ScatterTestApp().run()

scattertest.kv

#:kivy 1.0.9

<TextSquare>:
    canvas:
        Color:
            rgb: 0,0,0
        Rectangle:
            pos: 20,20
            size: 100,50
        Rectangle:
            pos: 30,30
            size: 80,30
    Label:
        font_size: 30  
        center_x: self.width / 2
        center_y: self.height / 2
        text: "Test"