diff --git a/lib/examples/dino.py b/lib/examples/dino.py
index 8ec9cec8..fc97720d 100644
--- a/lib/examples/dino.py
+++ b/lib/examples/dino.py
@@ -489,6 +489,8 @@ def draw(self):
                 self._draw_number(self.high_score, WIDTH - 24, score_color)
 
         display_drv.blit_rect(self.canvas.buffer, 0, 0, WIDTH, HEIGHT)
+        # A PixelDisplay has no needs_refresh, so appdev.App never presents it.
+        display_drv.show()
 
     def tick(self, _timer=None):
         app.poll()
diff --git a/lib/examples/pixel_sim_demos.py b/lib/examples/pixel_sim_demos.py
index 1d2781fb..89ae26df 100644
--- a/lib/examples/pixel_sim_demos.py
+++ b/lib/examples/pixel_sim_demos.py
@@ -94,6 +94,8 @@ def _randint(a, b):
 
 def _present(dest):
     display_drv.blit_rect(dest.buffer, 0, 0, GRID_W, GRID_H)
+    # A PixelDisplay has no needs_refresh, so appdev.App never presents it.
+    display_drv.show()
 
 
 # --- scroll -----------------------------------------------------------------