diff --git a/README.md b/README.md
index 260f3d4..821aa84 100644
--- a/README.md
+++ b/README.md
@@ -27,10 +27,11 @@ OPTIONS:
   -s <SPEED>          Set the speed, from 1 to 5. (default 1)
   -r <RADIUS>         Set the radius of the metaballs, from 1 to 10. (default: 5)
   -R <RIM>            Set a rim for each metaball, sizes from 1 to 5.(default: none)
+  -k <COLOR>          Set the color of the rim if there is one. Available colours: red, blue, yellow, green, cyan and magenta.
                       This option does not work with the default color.
   -b <NBALLS>         Set the number of metaballs in the simulation, from 2 to 20. (default: 10)
   -F <CHARS>          Allows for a custom set of chars to be used
-                      Only ascii symbols are supported for now, wide/unicode chars may appear broken.
+                      Only ascii symbols are supported for now, wide/unicode characters may appear broken.
   -C                  Retain the entire lava inside the terminal.
                       It may not work well with a lot of balls or with a bigger radius than the default one.
   -h                  Print help.