diff --git a/README.md b/README.md
index 7d00193..d625a51 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 
 Make beautiful maps.
 
+Very rough proof-of-concept for real-time raytracing or digital terrain models.
+
 ![Image of Spectacled Flying Fox](Spectacled_flying_fox.jpg)
 
 Spectacled Flying Fox image By CSIRO, [Creative Commons Attribution