diff --git a/rects/RectSaver.cpp b/rects/RectSaver.cpp
index 1634350..ac2e6a0 100644
--- a/rects/RectSaver.cpp
+++ b/rects/RectSaver.cpp
@@ -32,7 +32,7 @@ void RectSaver::update() {
 }
 
 void RectSaver::render() {
-    cairo_set_source_rgb(_c, random01(), random01(), random01());
+    cairo_set_source_rgba(_c, random01(), random01(), random01(), random01());
     cairo_rectangle_t rect {random_rect()};
     cairo_rectangle(_c, rect.x, rect.y, rect.width, rect.height);
     cairo_fill(_c);