diff --git a/README.md b/README.md
index ed1ff1b..abe6a73 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,4 @@
 * my first nim project https://nim-lang.org/
 * also: my first opengl project
+** manually translated from c++ from https://physicspython.wordpress.com/2020/02/16/visualizing-the-mandelbrot-set-using-opengl-part-1/
 * works at least on my mac