diff --git a/src/main.c b/src/main.c
index b945f95..459ae84 100644
--- a/src/main.c
+++ b/src/main.c
@@ -18,6 +18,9 @@ static void do_draw(void)
   Fb_filled_rectangle(10, 60, 50, 100, FBPRIMCLR_CYAN, FALSE);
   Fb_filled_rectangle(60, 60, 100, 100, FBPRIMCLR_MAGENTA, FALSE);
   Fb_filled_rectangle(110, 60, 150, 100, FBPRIMCLR_YELLOW, FALSE);
+  Fb_rectangle(10, 110, 150, 150, PBPRIMCLR_WHITE, FALSE);
+  Fb_line(10, 110, 150, 150, FBPRIMCLR_WHITE, FALSE);
+  Fb_line(10, 150, 150, 110, FBPRIMCLR_WHITE, FALSE);
 }
 
 static void log_touch(const char *event, UINT_PTR x, UINT_PTR y)