docs: 0,0 coords and new points

README.md

@@ -55,6 +55,17 @@ You can pipe it to a graphical program or save it to file.
 ./ppppcg > pc.svg  # to file
 ```
 
+Add some of your own points.
+
+```yaml
+points:
+  - {name: "???", x: 50, y: 450}
+  - {name: moar, x: 50, y: 450}
+  # and so on ...
+```
+
+The `(0, 0)` coordinates are the top leftmost corner of the canvas.
+
 👋
 
 ## License