diff --git a/assets/test_prelude.ld b/assets/test_prelude.ld
index 579c748..c681308 100644
--- a/assets/test_prelude.ld
+++ b/assets/test_prelude.ld
@@ -1023,6 +1023,7 @@ let colors = #{
 	:black (0, 0, 0, 255)
 	:silver (192, 192, 192, 255)
 	:gray (128, 128, 128, 255)
+	:grey (128, 128, 128, 255)
 	:white (255, 255, 255, 255)
 	:maroon (128, 0, 0, 255)
 	:red (255, 0, 0, 255)
@@ -1038,6 +1039,8 @@ let colors = #{
 	:aqua (0, 255, 25, 255)
 }
 
+let colours = colors
+
 & the initial turtle state
 let turtle_init = #{
 	:position (0, 0) & let's call this the origin for now
@@ -1117,6 +1120,8 @@ fn pencolor! {
 	((r as :number, g as :number, b as :number, a as :number)) -> add_command! (:turtle_0, (:pencolor, (r, g, b, a)))
 }
 
+let pencolour! = pencolor!
+
 let pc! = pencolor!
 
 fn penwidth! {
@@ -1233,6 +1238,8 @@ fn pencolor {
 	() -> do turtle_states > unbox > :turtle_0 > :pencolor
 }
 
+let pencolour = pencolor
+
 fn penwidth {
 	"Returns the turtle's pen width in pixels."
 	() -> do turtle_states > unbox > :turtle_0 > :penwidth
@@ -1415,6 +1422,7 @@ fn read_input {
 	clear!
 	coll?
 	colors
+	colours
 	concat
 	cons
 	console
@@ -1493,6 +1501,7 @@ fn read_input {
 	pd!
 	pencolor
 	pencolor!
+	pencolour!
 	pendown!
 	pendown?
 	penup!
diff --git a/pkg/rudus_bg.wasm b/pkg/rudus_bg.wasm
index af2293c..648f14b 100644
Binary files a/pkg/rudus_bg.wasm and b/pkg/rudus_bg.wasm differ