diff --git a/source/Buoy-Collections-GS64-Extensions/Array.extension.st b/source/Buoy-Collections-GS64-Extensions/Array.extension.st
index e8b3ab5..1554cf4 100644
--- a/source/Buoy-Collections-GS64-Extensions/Array.extension.st
+++ b/source/Buoy-Collections-GS64-Extensions/Array.extension.st
@@ -8,3 +8,14 @@ Array >> fillFrom: aCollection with: aBlock [
 	aCollection do: [ :each |
 		self at: (index := index + 1) put: (aBlock value: each) ]
 ]
+
+{ #category : #'*Buoy-Collections-GS64-Extensions' }
+Array class >> newFrom: aCollection [
+	"Answer an instance of me containing the same elements as aCollection."
+
+	| newArray |
+	newArray := self new: aCollection size.
+	1 to: aCollection size do: [ :i |
+	newArray at: i put: (aCollection at: i) ].
+	^ newArray
+]
diff --git a/source/Buoy-Collections-GS64-Extensions/Collection.extension.st b/source/Buoy-Collections-GS64-Extensions/Collection.extension.st
index c387dae..14a459a 100644
--- a/source/Buoy-Collections-GS64-Extensions/Collection.extension.st
+++ b/source/Buoy-Collections-GS64-Extensions/Collection.extension.st
@@ -6,6 +6,15 @@ Collection >> anyOne [
 	^ self any
 ]
 
+{ #category : #'*Buoy-Collections-GS64-Extensions' }
+Collection >> as: aSimilarClass [
+	"Create an object of class aSimilarClass that has similar contents to the receiver if the object is not already an instance of this class."
+
+	aSimilarClass == self class ifTrue: [ ^ self ].
+
+	^ aSimilarClass newFrom: self
+]
+
 { #category : #'*Buoy-Collections-GS64-Extensions' }
 Collection >> collect: aBlock as: aClass [
 	"Evaluate aBlock with each of the receiver's elements as the argument.
@@ -38,6 +47,16 @@ Collection >> isSequenceable [
 	^ false
 ]
 
+{ #category : #'*Buoy-Collections-GS64-Extensions' }
+Collection class >> newFrom: aCollection [
+	"Answer an instance of me containing the same elements as aCollection."
+
+	| newCollection |
+	newCollection := self new: aCollection size.
+	newCollection addAll: aCollection.
+	^ newCollection
+]
+
 { #category : #'*Buoy-Collections-GS64-Extensions' }
 Collection >> select: selectBlock thenCollect: collectBlock [
 
diff --git a/source/Buoy-Collections-GS64-Extensions/SequenceableCollection.extension.st b/source/Buoy-Collections-GS64-Extensions/SequenceableCollection.extension.st
index 99275fb..8cfcc9f 100644
--- a/source/Buoy-Collections-GS64-Extensions/SequenceableCollection.extension.st
+++ b/source/Buoy-Collections-GS64-Extensions/SequenceableCollection.extension.st
@@ -5,3 +5,8 @@ SequenceableCollection >> isSequenceable [
 
 	^ true
 ]
+
+{ #category : #'*Buoy-Collections-GS64-Extensions' }
+SequenceableCollection >> writeStream [
+	^ WriteStream on: self
+]