diff --git a/subjects/printnbrinorder.en.md b/subjects/printnbrinorder.en.md
index 832b6cb7..42ee8b7d 100644
--- a/subjects/printnbrinorder.en.md
+++ b/subjects/printnbrinorder.en.md
@@ -34,7 +34,7 @@ And its output :
 
 ```console
 student@ubuntu:~/[[ROOT]]/test$ go build
-student@ubuntu:~/[[ROOT]]/test$ ./test
-1230123
+student@ubuntu:~/[[ROOT]]/test$ ./test | cat -e
+1230123$
 student@ubuntu:~/[[ROOT]]/test$
 ```
diff --git a/tests/go/func/broken/correct/printnbrbase.go b/tests/go/func/broken/correct/printnbrbase.go
index fa8b158c..26a373d0 100644
--- a/tests/go/func/broken/correct/printnbrbase.go
+++ b/tests/go/func/broken/correct/printnbrbase.go
@@ -1,6 +1,6 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
 func PrintNbrBase(n int, base string) {
 	if validBase(base) {
@@ -8,17 +8,16 @@ func PrintNbrBase(n int, base string) {
 		sign := 1
 		rbase := []rune(base)
 		if n < 0 {
-			z01.PrintRune('-')
+			fmt.Print("-")
 			sign = -1
 		}
 		if n < length && n >= 0 {
-			z01.PrintRune(rbase[n])
+			fmt.Printf("%c", rbase[n])
 		} else {
 			PrintNbrBase(sign*(n/length), base)
-			z01.PrintRune(rbase[sign*(n%length)])
+			fmt.Printf("%c", rbase[sign*(n%length)])
 		}
 	} else {
-		z01.PrintRune('N')
-		z01.PrintRune('V')
+		fmt.Print("NV")
 	}
 }
diff --git a/tests/go/func/correct/eightqueens.go b/tests/go/func/correct/eightqueens.go
index c5a28670..7b2961e0 100644
--- a/tests/go/func/correct/eightqueens.go
+++ b/tests/go/func/correct/eightqueens.go
@@ -1,6 +1,6 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
 const size = 8
 
@@ -44,13 +44,13 @@ func printQueens() {
 		for y < size {
 			if board[x][y] {
 				// We have found a queen, let's print her y
-				z01.PrintRune(rune(y) + '1')
+				fmt.Printf("%c", rune(y)+'1')
 			}
 			y++
 		}
 		x++
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 }
 
 // tryX tries, for a given x (column) to find a y (row) so that the queen on (x, y) is a part
diff --git a/tests/go/func/correct/printchessboard.go b/tests/go/func/correct/printchessboard.go
index 0a24e296..45c588fe 100644
--- a/tests/go/func/correct/printchessboard.go
+++ b/tests/go/func/correct/printchessboard.go
@@ -1,19 +1,11 @@
 package correct
 
 import (
+	"fmt"
 	"os"
 	"strconv"
-
-	"github.com/01-edu/z01"
 )
 
-func printLineCh(str string) {
-	for _, c := range str {
-		z01.PrintRune(c)
-	}
-	z01.PrintRune('\n')
-}
-
 func solve(x, y int) {
 	for i := 0; i < x; i++ {
 		line := ""
@@ -28,20 +20,20 @@ func solve(x, y int) {
 				line += " "
 			}
 		}
-		printLineCh(line)
+		fmt.Println(line)
 	}
 }
 
 func main() {
 	args := os.Args[1:]
 	if len(args) != 2 {
-		printLineCh("Error")
+		fmt.Println("Error")
 		return
 	}
 	x, _ := strconv.Atoi(args[1])
 	y, _ := strconv.Atoi(args[0])
 	if x <= 0 || y <= 0 {
-		printLineCh("Error")
+		fmt.Println("Error")
 		return
 	}
 	solve(x, y)
diff --git a/tests/go/func/correct/printcomb.go b/tests/go/func/correct/printcomb.go
index c5e98d48..3a81cd9f 100644
--- a/tests/go/func/correct/printcomb.go
+++ b/tests/go/func/correct/printcomb.go
@@ -1,19 +1,16 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
 func PrintComb() {
 	for i := '0'; i <= '7'; i++ {
 		for j := i + 1; j <= '8'; j++ {
 			for k := j + 1; k <= '9'; k++ {
-				z01.PrintRune(rune(i))
-				z01.PrintRune(rune(j))
-				z01.PrintRune(rune(k))
+				fmt.Printf("%c%c%c", i, j, k)
 				if i < '7' {
-					z01.PrintRune(rune(','))
-					z01.PrintRune(rune(' '))
+					fmt.Printf(", ")
 				} else {
-					z01.PrintRune(rune('\n'))
+					fmt.Println()
 				}
 			}
 		}
diff --git a/tests/go/func/correct/printmemory.go b/tests/go/func/correct/printmemory.go
index ae967584..309a4b0f 100644
--- a/tests/go/func/correct/printmemory.go
+++ b/tests/go/func/correct/printmemory.go
@@ -1,9 +1,8 @@
 package correct
 
 import (
+	"fmt"
 	"unicode"
-
-	"github.com/01-edu/z01"
 )
 
 func printBase(nbr int) int {
@@ -28,7 +27,7 @@ func printBase(nbr int) int {
 		i = 2
 	}
 	for j := i - 1; j >= 0; j-- {
-		z01.PrintRune(result[j])
+		fmt.Printf("%c", result[j])
 		a++
 	}
 	return a
@@ -41,42 +40,42 @@ func printLine(arr [10]int, start int) {
 
 	for a < start+16 && a < size {
 		if a%4 == 0 && a != 0 {
-			z01.PrintRune('\n')
+			fmt.Println()
 		}
 		b = 8 - printBase(arr[a])
 		for aux != b {
 			if b == 6 {
-				z01.PrintRune('0')
+				fmt.Print("0")
 			}
 			if aux == 1 {
-				z01.PrintRune(' ')
+				fmt.Print(" ")
 			}
 			if b < 6 {
-				z01.PrintRune('0')
+				fmt.Print("0")
 			}
 			aux++
 		}
-		z01.PrintRune(' ')
+		fmt.Print(" ")
 		aux = 0
 		a++
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 	c := start
 	for c < start+16 && c < size {
 		if unicode.IsPrint(rune(arr[c])) {
-			z01.PrintRune(rune(arr[c]))
+			fmt.Printf("%c", rune(arr[c]))
 		} else {
-			z01.PrintRune('.')
+			fmt.Print(".")
 		}
 		c++
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 }
 
-func PrintMemory(arr [10]int) {
+func PrintMemory(a [10]int) {
 	i := 0
-	for i < len(arr) {
-		printLine(arr, i)
+	for i < len(a) {
+		printLine(a, i)
 		i += 16
 	}
 }
diff --git a/tests/go/func/correct/printnbrinorder.go b/tests/go/func/correct/printnbrinorder.go
index ff436b8f..1a435b3a 100644
--- a/tests/go/func/correct/printnbrinorder.go
+++ b/tests/go/func/correct/printnbrinorder.go
@@ -1,9 +1,8 @@
 package correct
 
 import (
+	"fmt"
 	"sort"
-
-	"github.com/01-edu/z01"
 )
 
 func intToDigits(n int) (digits []int) {
@@ -20,12 +19,13 @@ func intToDigits(n int) (digits []int) {
 
 func PrintNbrInOrder(n int) {
 	if n == 0 {
-		z01.PrintRune('0')
+		fmt.Print("0")
 		return
 	}
 	digits := intToDigits(n)
 	sort.Ints(digits)
 	for _, i := range digits {
-		z01.PrintRune(rune(i) + '0')
+		fmt.Printf("%c", rune(i)+'0')
 	}
+	fmt.Println()
 }
diff --git a/tests/go/func/correct/raid1a.go b/tests/go/func/correct/raid1a.go
index 288d99a5..c32d2184 100644
--- a/tests/go/func/correct/raid1a.go
+++ b/tests/go/func/correct/raid1a.go
@@ -1,24 +1,23 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
-func drawLine(x int, str string) {
-	strConverted := []rune(str)
-	beg := strConverted[0]
-	med := strConverted[1]
-	end := strConverted[2]
+func drawLine(x int, s string) {
+	beg := s[0]
+	med := s[1]
+	end := s[2]
 	if x >= 1 {
-		z01.PrintRune(beg)
+		fmt.Printf("%c", beg)
 	}
 	if x > 2 {
 		for i := 0; i < (x - 2); i++ {
-			z01.PrintRune(med)
+			fmt.Printf("%c", med)
 		}
 	}
 	if x > 1 {
-		z01.PrintRune(end)
+		fmt.Printf("%c", end)
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 }
 
 func printTheLines(x, y int, strBeg, strMed, strEnd string) {
diff --git a/tests/go/func/correct/raid1b.go b/tests/go/func/correct/raid1b.go
index dbe96fae..a7629dcf 100644
--- a/tests/go/func/correct/raid1b.go
+++ b/tests/go/func/correct/raid1b.go
@@ -1,24 +1,23 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
-func drawLineRaid1b(x int, str string) {
-	strConverted := []rune(str)
-	beg := strConverted[0]
-	med := strConverted[1]
-	end := strConverted[2]
+func drawLineRaid1b(x int, s string) {
+	beg := s[0]
+	med := s[1]
+	end := s[2]
 	if x >= 1 {
-		z01.PrintRune(beg)
+		fmt.Printf("%c", beg)
 	}
 	if x > 2 {
 		for i := 0; i < (x - 2); i++ {
-			z01.PrintRune(med)
+			fmt.Printf("%c", med)
 		}
 	}
 	if x > 1 {
-		z01.PrintRune(end)
+		fmt.Printf("%c", end)
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 }
 
 func Raid1b(x, y int) {
diff --git a/tests/go/func/correct/raid1c.go b/tests/go/func/correct/raid1c.go
index fb4e5515..bb61d9ba 100644
--- a/tests/go/func/correct/raid1c.go
+++ b/tests/go/func/correct/raid1c.go
@@ -1,24 +1,23 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
-func drawLineRaid1c(x int, str string) {
-	strConverted := []rune(str)
-	beg := strConverted[0]
-	med := strConverted[1]
-	end := strConverted[2]
+func drawLineRaid1c(x int, s string) {
+	beg := s[0]
+	med := s[1]
+	end := s[2]
 	if x >= 1 {
-		z01.PrintRune(beg)
+		fmt.Printf("%c", beg)
 	}
 	if x > 2 {
 		for i := 0; i < (x - 2); i++ {
-			z01.PrintRune(med)
+			fmt.Printf("%c", med)
 		}
 	}
 	if x > 1 {
-		z01.PrintRune(end)
+		fmt.Printf("%c", end)
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 }
 
 func Raid1c(x, y int) {
diff --git a/tests/go/func/correct/raid1d.go b/tests/go/func/correct/raid1d.go
index a18b3814..eedf5e74 100644
--- a/tests/go/func/correct/raid1d.go
+++ b/tests/go/func/correct/raid1d.go
@@ -1,24 +1,23 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
-func drawLineRaid1d(x int, str string) {
-	strConverted := []rune(str)
-	beg := strConverted[0]
-	med := strConverted[1]
-	end := strConverted[2]
+func drawLineRaid1d(x int, s string) {
+	beg := s[0]
+	med := s[1]
+	end := s[2]
 	if x >= 1 {
-		z01.PrintRune(beg)
+		fmt.Printf("%c", beg)
 	}
 	if x > 2 {
 		for i := 0; i < (x - 2); i++ {
-			z01.PrintRune(med)
+			fmt.Printf("%c", med)
 		}
 	}
 	if x > 1 {
-		z01.PrintRune(end)
+		fmt.Printf("%c", end)
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 }
 
 func Raid1d(x, y int) {
diff --git a/tests/go/func/correct/raid1e.go b/tests/go/func/correct/raid1e.go
index a2190d65..4eb967e9 100644
--- a/tests/go/func/correct/raid1e.go
+++ b/tests/go/func/correct/raid1e.go
@@ -1,24 +1,23 @@
 package correct
 
-import "github.com/01-edu/z01"
+import "fmt"
 
-func drawLineRaid1e(x int, str string) {
-	strConverted := []rune(str)
-	beg := strConverted[0]
-	med := strConverted[1]
-	end := strConverted[2]
+func drawLineRaid1e(x int, s string) {
+	beg := s[0]
+	med := s[1]
+	end := s[2]
 	if x >= 1 {
-		z01.PrintRune(beg)
+		fmt.Printf("%c", beg)
 	}
 	if x > 2 {
 		for i := 0; i < (x - 2); i++ {
-			z01.PrintRune(med)
+			fmt.Printf("%c", med)
 		}
 	}
 	if x > 1 {
-		z01.PrintRune(end)
+		fmt.Printf("%c", end)
 	}
-	z01.PrintRune('\n')
+	fmt.Println()
 }
 
 func Raid1e(x, y int) {
diff --git a/tests/go/prog/test_tetrisoptimizer.go b/tests/go/prog/test_tetrisoptimizer.go
index 558afdc2..e2f8fe16 100644
--- a/tests/go/prog/test_tetrisoptimizer.go
+++ b/tests/go/prog/test_tetrisoptimizer.go
@@ -28,8 +28,7 @@ type (
 	tetromino [3]vect
 )
 
-// load a tetromino composed of the rune r in the map s
-// example :
+// load a tetromino composed of the rune r in the map s, example :
 //
 // read(`......
 // ......
@@ -40,7 +39,6 @@ type (
 // `,
 //     'X',
 // ) == tetromino{{-2, 1}, {-1, 1}, {0, 1}}
-
 func read(s string, r rune) (t tetromino) {
 	var origin vect
 	i := 0