diff --git a/moo/kernel/Collect.moo b/moo/kernel/Collect.moo
index b81bfab..7727981 100644
--- a/moo/kernel/Collect.moo
+++ b/moo/kernel/Collect.moo
@@ -21,6 +21,15 @@ class Collection(Object)
 		^count
 	}
 
+	method add: object
+	{
+		self subclassResponsibility: #add:.
+	}
+
+	## ===================================================================
+	## ENUMERATION
+	## ===================================================================
+
 	method do: block
 	{
 		^self subclassResponsibility: #do
@@ -37,13 +46,6 @@ class Collection(Object)
 		^exception_block value.
 	}
 
-(* ------------------- TODO -------------------------------
-	method add: object
-	{
-		self subclassResponsibility: #add:.
-	}
-*)
-
 	method collect: block
 	{
 		| coll |
@@ -924,32 +926,38 @@ class Set(Collection)
 
 	method do: block
 	{
-		| bs |
+		| bs i ass |
 		bs := self.bucket size.
-		0 priorTo: bs by: 1 do: [:i |
-			| ass |
+		i := 0.
+		while (i < bs)
+		{
 			if ((ass := self.bucket at: i) notNil) { block value: ass value }.
-		].
+			i := i + 1.
+		}.
 	}
-	
+
 	method keysDo: block
 	{
-		| bs |
+		| bs i ass |
 		bs := self.bucket size.
-		0 priorTo: bs by: 1 do: [:i |
-			| ass |
+		i := 0.
+		while (i < bs)
+		{
 			if ((ass := self.bucket at: i) notNil) { block value: ass key }.
-		].
+			i := i + 1.
+		}.
 	}
 
 	method keysAndValuesDo: block
 	{
-		| bs |
+		| bs i ass |
 		bs := self.bucket size.
-		0 priorTo: bs by: 1 do: [:i |
-			| ass |
+		i := 0.
+		while (i < bs)
+		{
 			if ((ass := self.bucket at: i) notNil)  { block value: ass key value: ass value }.
-		].	
+			i := i + 1.
+		}.
 	}
 }
 
diff --git a/moo/kernel/Mill.moo b/moo/kernel/Mill.moo
index 908e105..b6b3fbd 100644
--- a/moo/kernel/Mill.moo
+++ b/moo/kernel/Mill.moo
@@ -95,7 +95,7 @@ class MyObject(Object)
 			(ffi call: #printf signature: 's|iis)i' arguments: #(S'A=>%d B=>%d Hello, world %s\n' 1 2 'fly away')) dump.
 			(ffi call: #printf signature: 's|iis)i' arguments: #(S'A=>%d B=>%d Hello, world %s\n' 1 2 'jump down')) dump.
 			ffi close.
-		}.
+		}. 
 		(('abcd' == 'abcd') ifTrue: [1] ifFalse: [2]) dump.
 
 	}
@@ -325,7 +325,7 @@ i := 0.
 while (i < 26)
 {
 	a putUint8(i, ($A asInteger + i)).
-	System _putUint8(a, i, ($A asInteger + i)).
+	System putUint8(a, i, ($A asInteger + i)).
 	i := i + 1.
 }.
 while (i > 0)
diff --git a/moo/kernel/System.moo b/moo/kernel/System.moo
index c31f505..dd85da5 100644
--- a/moo/kernel/System.moo
+++ b/moo/kernel/System.moo
@@ -110,7 +110,7 @@ class System(Apex)
 		## -----------------------------------------------------
 		| s |
 		s := Semaphore new.
-		self signal: s afterSecs: secs.
+		s signalAfterSecs: secs.
 		s wait.
 	}
 
@@ -121,7 +121,7 @@ class System(Apex)
 		## -----------------------------------------------------
 		| s |
 		s := Semaphore new.
-		self signal: s afterSecs: secs nanosecs: nanosecs.
+		s signalAfterSecs: secs nanosecs: nanosecs.
 		s wait.
 	}
 }