diff --git a/SketchWidget.py b/SketchWidget.py
index 76185f4..a189cb5 100644
--- a/SketchWidget.py
+++ b/SketchWidget.py
@@ -115,6 +115,13 @@ class SketchWidget:
         glVertex(x1 + x_right, y1 + y_right)
         glVertex(x1 + x_left, y1 + y_left)
         glEnd()
+        self.drawFilledCircle(x0, y0, size, 16)
+        self.drawFilledCircle(x1, y1, size, 16)
 
     def drawFilledCircle(self, x, y, radius, steps):
-        pass
+        glBegin(GL_TRIANGLE_FAN)
+        glVertex(x, y)
+        for i in range(steps + 1):
+            angle = i * 2 * math.pi / steps
+            glVertex(x + radius * math.cos(angle), y + radius * math.sin(angle))
+        glEnd()