diff --git a/subjects/btreeapplybylevel.en.md b/subjects/btreeapplybylevel.en.md
index 85cd3eb04..e964f86af 100644
--- a/subjects/btreeapplybylevel.en.md
+++ b/subjects/btreeapplybylevel.en.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeApplyByLevel, that applies the function given by fn to each node of the tree given by root.
+Write a function, `BTreeApplyByLevel`, that applies the function given by fn to each node of the tree given by root.
 
 This function must have the following signature.
 
@@ -23,26 +23,26 @@ package main
 
 import (
 	"fmt"
-	student ".."
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	student.BTreeApplyByLevel(root, fmt.Println)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	piscine.BTreeApplyByLevel(root, fmt.Println)
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreeapplybylevel$ go build
-student@ubuntu:~/student/btreeapplybylevel$ ./btreeapplybylevel
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 4
 1
 7
 5
-student@ubuntu:~/student/btreeapplybylevel$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreeapplybylevel.fr.md b/subjects/btreeapplybylevel.fr.md
index 85cd3eb04..e964f86af 100644
--- a/subjects/btreeapplybylevel.fr.md
+++ b/subjects/btreeapplybylevel.fr.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeApplyByLevel, that applies the function given by fn to each node of the tree given by root.
+Write a function, `BTreeApplyByLevel`, that applies the function given by fn to each node of the tree given by root.
 
 This function must have the following signature.
 
@@ -23,26 +23,26 @@ package main
 
 import (
 	"fmt"
-	student ".."
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	student.BTreeApplyByLevel(root, fmt.Println)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	piscine.BTreeApplyByLevel(root, fmt.Println)
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreeapplybylevel$ go build
-student@ubuntu:~/student/btreeapplybylevel$ ./btreeapplybylevel
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 4
 1
 7
 5
-student@ubuntu:~/student/btreeapplybylevel$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreeisbinary.en.md b/subjects/btreeisbinary.en.md
index e57a11a95..2a93d3143 100644
--- a/subjects/btreeisbinary.en.md
+++ b/subjects/btreeisbinary.en.md
@@ -23,23 +23,23 @@ package main
 
 import (
 	"fmt"
-	student ".."
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	fmt.Println(student.BTreeIsBinary(root))
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	fmt.Println(piscine.BTreeIsBinary(root))
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreeisbinary$ go build
-student@ubuntu:~/student/btreeisbinary$ ./btreeisbinary
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 true
-student@ubuntu:~/student/btreeisbinary$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreeisbinary.fr.md b/subjects/btreeisbinary.fr.md
index e57a11a95..2a93d3143 100644
--- a/subjects/btreeisbinary.fr.md
+++ b/subjects/btreeisbinary.fr.md
@@ -23,23 +23,23 @@ package main
 
 import (
 	"fmt"
-	student ".."
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	fmt.Println(student.BTreeIsBinary(root))
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	fmt.Println(piscine.BTreeIsBinary(root))
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreeisbinary$ go build
-student@ubuntu:~/student/btreeisbinary$ ./btreeisbinary
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 true
-student@ubuntu:~/student/btreeisbinary$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreelevelcount.en.md b/subjects/btreelevelcount.en.md
index 2576e1099..ef9c7806f 100644
--- a/subjects/btreelevelcount.en.md
+++ b/subjects/btreelevelcount.en.md
@@ -7,7 +7,7 @@ Write a function, BTreeLevelCount, that return the number of levels of the tree
 ### Expected function
 
 ```go
-func BTreeLevelCount(root *piscine.TreeNode) int {
+func BTreeLevelCount(root *TreeNode) int {
 
 }
 ```
@@ -21,23 +21,24 @@ package main
 
 import (
 	"fmt"
-	student ".."
+
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	fmt.Println(BTreeLevelCount(root))
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	fmt.Println(piscine.BTreeLevelCount(root))
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreesearchitem$ go build
-student@ubuntu:~/student/btreesearchitem$ ./btreesearchitem
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 3
-student@ubuntu:~/student/btreesearchitem$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreelevelcount.fr.md b/subjects/btreelevelcount.fr.md
index 2576e1099..ef9c7806f 100644
--- a/subjects/btreelevelcount.fr.md
+++ b/subjects/btreelevelcount.fr.md
@@ -7,7 +7,7 @@ Write a function, BTreeLevelCount, that return the number of levels of the tree
 ### Expected function
 
 ```go
-func BTreeLevelCount(root *piscine.TreeNode) int {
+func BTreeLevelCount(root *TreeNode) int {
 
 }
 ```
@@ -21,23 +21,24 @@ package main
 
 import (
 	"fmt"
-	student ".."
+
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	fmt.Println(BTreeLevelCount(root))
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	fmt.Println(piscine.BTreeLevelCount(root))
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreesearchitem$ go build
-student@ubuntu:~/student/btreesearchitem$ ./btreesearchitem
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 3
-student@ubuntu:~/student/btreesearchitem$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreemax.en.md b/subjects/btreemax.en.md
index dc389960b..3fa2bc5c3 100644
--- a/subjects/btreemax.en.md
+++ b/subjects/btreemax.en.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeMax, that returns the node with the maximum value in the tree given by root
+Write a function, `BTreeMax`, that returns the node with the maximum value in the tree given by root
 
 This function must have the following signature.
 
@@ -23,15 +23,16 @@ package main
 
 import (
 	"fmt"
-	student ".."
+
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	max := student.BTreeMax(root)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	max := piscine.BTreeMax(root)
 	fmt.Println(max.Data)
 }
 ```
@@ -39,8 +40,8 @@ func main() {
 And its output :
 
 ```console
-student@ubuntu:~/student/btreemax$ go build
-student@ubuntu:~/student/btreemax$ ./btreemax
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 7
-student@ubuntu:~/student/btreemax$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreemax.fr.md b/subjects/btreemax.fr.md
index dc389960b..3fa2bc5c3 100644
--- a/subjects/btreemax.fr.md
+++ b/subjects/btreemax.fr.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeMax, that returns the node with the maximum value in the tree given by root
+Write a function, `BTreeMax`, that returns the node with the maximum value in the tree given by root
 
 This function must have the following signature.
 
@@ -23,15 +23,16 @@ package main
 
 import (
 	"fmt"
-	student ".."
+
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	max := student.BTreeMax(root)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	max := piscine.BTreeMax(root)
 	fmt.Println(max.Data)
 }
 ```
@@ -39,8 +40,8 @@ func main() {
 And its output :
 
 ```console
-student@ubuntu:~/student/btreemax$ go build
-student@ubuntu:~/student/btreemax$ ./btreemax
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 7
-student@ubuntu:~/student/btreemax$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreemin.en.md b/subjects/btreemin.en.md
index f34718569..8de2f9a04 100644
--- a/subjects/btreemin.en.md
+++ b/subjects/btreemin.en.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeMin, that returns the node with the minimum value in the tree given by root
+Write a function, `BTreeMin`, that returns the node with the minimum value in the tree given by root
 
 This function must have the following signature.
 
@@ -23,15 +23,16 @@ package main
 
 import (
 	"fmt"
-	student ".."
+
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	min := student.BTreeMin(root)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	min := piscine.BTreeMin(root)
 	fmt.Println(min.Data)
 }
 ```
@@ -39,8 +40,8 @@ func main() {
 And its output :
 
 ```console
-student@ubuntu:~/student/btreemin$ go build
-student@ubuntu:~/student/btreemin$ ./btreemin
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 1
-student@ubuntu:~/student/btreemin$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreemin.fr.md b/subjects/btreemin.fr.md
index f34718569..8de2f9a04 100644
--- a/subjects/btreemin.fr.md
+++ b/subjects/btreemin.fr.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeMin, that returns the node with the minimum value in the tree given by root
+Write a function, `BTreeMin`, that returns the node with the minimum value in the tree given by root
 
 This function must have the following signature.
 
@@ -23,15 +23,16 @@ package main
 
 import (
 	"fmt"
-	student ".."
+
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	min := student.BTreeMin(root)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	min := piscine.BTreeMin(root)
 	fmt.Println(min.Data)
 }
 ```
@@ -39,8 +40,8 @@ func main() {
 And its output :
 
 ```console
-student@ubuntu:~/student/btreemin$ go build
-student@ubuntu:~/student/btreemin$ ./btreemin
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 1
-student@ubuntu:~/student/btreemin$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreetransplant.en.md b/subjects/btreetransplant.en.md
index e80939149..0e8438a7f 100644
--- a/subjects/btreetransplant.en.md
+++ b/subjects/btreetransplant.en.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-In order to move subtrees around within the binary search tree, write a function, BTreeTransplant, which replaces the subtree started by node with the node called 'rplc' in the tree given by root.
+In order to move subtrees around within the binary search tree, write a function, `BTreeTransplant`, which replaces the subtree started by node with the node called `rplc` in the tree given by root.
 
 This function must have the following signature.
 
@@ -23,29 +23,29 @@ package main
 
 import (
 	"fmt"
-	student ".."
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	node := student.BTreeSearchItem(root, "1")
-	replacement := &student.TreeNode{Data: "3"}
-	root = student.BTreeTransplant(root, node, replacement)
-	student.BTreeApplyInorder(root, fmt.Println)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	node := piscine.BTreeSearchItem(root, "1")
+	replacement := &piscine.TreeNode{Data: "3"}
+	root = piscine.BTreeTransplant(root, node, replacement)
+	piscine.BTreeApplyInorder(root, fmt.Println)
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreetransplant$ go build
-student@ubuntu:~/student/btreetrandsplant$ ./btreetransplant
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 3
 4
 5
 7
-student@ubuntu:~/student/btreetrandsplant$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/btreetransplant.fr.md b/subjects/btreetransplant.fr.md
index e80939149..0e8438a7f 100644
--- a/subjects/btreetransplant.fr.md
+++ b/subjects/btreetransplant.fr.md
@@ -2,7 +2,7 @@
 
 ### Instructions
 
-In order to move subtrees around within the binary search tree, write a function, BTreeTransplant, which replaces the subtree started by node with the node called 'rplc' in the tree given by root.
+In order to move subtrees around within the binary search tree, write a function, `BTreeTransplant`, which replaces the subtree started by node with the node called `rplc` in the tree given by root.
 
 This function must have the following signature.
 
@@ -23,29 +23,29 @@ package main
 
 import (
 	"fmt"
-	student ".."
+	piscine ".."
 )
 
 func main() {
-	root := &student.TreeNode{Data: "4"}
-	student.BTreeInsertData(root, "1")
-	student.BTreeInsertData(root, "7")
-	student.BTreeInsertData(root, "5")
-	node := student.BTreeSearchItem(root, "1")
-	replacement := &student.TreeNode{Data: "3"}
-	root = student.BTreeTransplant(root, node, replacement)
-	student.BTreeApplyInorder(root, fmt.Println)
+	root := &piscine.TreeNode{Data: "4"}
+	piscine.BTreeInsertData(root, "1")
+	piscine.BTreeInsertData(root, "7")
+	piscine.BTreeInsertData(root, "5")
+	node := piscine.BTreeSearchItem(root, "1")
+	replacement := &piscine.TreeNode{Data: "3"}
+	root = piscine.BTreeTransplant(root, node, replacement)
+	piscine.BTreeApplyInorder(root, fmt.Println)
 }
 ```
 
 And its output :
 
 ```console
-student@ubuntu:~/student/btreetransplant$ go build
-student@ubuntu:~/student/btreetrandsplant$ ./btreetransplant
+student@ubuntu:~/student/test$ go build
+student@ubuntu:~/student/test$ ./test
 3
 4
 5
 7
-student@ubuntu:~/student/btreetrandsplant$
+student@ubuntu:~/student/test$
 ```
diff --git a/subjects/listforeach.en.md b/subjects/listforeach.en.md
index 025c0e529..76359adbb 100644
--- a/subjects/listforeach.en.md
+++ b/subjects/listforeach.en.md
@@ -4,22 +4,42 @@
 
 Write a function `ListForEach` that applies a function given as argument to the information within each of the list's links.
 
-- The function given as argument must have a pointer as argument: `l *list`
+- The function given as argument must have a pointer as argument: `l *List`
+
+- Copy the functions `Add2_node` and `Subtract3_node` in the same file you defined the function `ListForEach`.
 
 ### Expected function and structure
 
 ```go
-type node struct {
-	data interface{}
-	next *node
+type NodeL struct {
+	Data interface{}
+	Next *NodeL
+}
+
+type List struct {
+	Head *NodeL
+	Tail *NodeL
 }
 
-type list struct {
-	head *node
-	tail *node
+func ListForEach(l *List, f func(*NodeL)) {
 }
 
-func ListForEach(l *list, f func(l *list)) {
+func Add2_node(node *NodeL) {
+	switch node.Data.(type) {
+	case int:
+		node.Data = node.Data.(int) + 2
+	case string:
+		node.Data = node.Data.(string) + "2"
+	}
+}
+
+func Subtract3_node(node *NodeL) {
+	switch node.Data.(type) {
+	case int:
+		node.Data = node.Data.(int) - 3
+	case string:
+		node.Data = node.Data.(string) + "-3"
+	}
 }
 ```
 
@@ -36,18 +56,19 @@ import (
 )
 
 func main() {
-	link := &list{}
+	link := &piscine.List{}
 
-	piscine.ListPushBack(link, 1)
-	piscine.ListPushBack(link, 2)
-	piscine.ListPushBack(link, 3)
-	piscine.ListPushBack(link, 4)
+	piscine.ListPushBack(link, "1")
+	piscine.ListPushBack(link, "2")
+	piscine.ListPushBack(link, "3")
+	piscine.ListPushBack(link, "5")
 
-	piscine.ListForEach(link, piscine.ListReverse)
+	piscine.ListForEach(link, piscine.Add2)
 
-	for link.head != nil {
-		fmt.Println(link.head.data)
-		link.head = link.head.next
+	it := link.Head
+	for it != nil {
+		fmt.Println(it.Data)
+		it = it.Next
 	}
 }
 ```
@@ -57,9 +78,9 @@ And its output :
 ```console
 student@ubuntu:~/piscine/test$ go build
 student@ubuntu:~/piscine/test$ ./test
-4
-3
-2
-1
+12
+22
+32
+52
 student@ubuntu:~/piscine/test$
 ```