diff --git a/buffer.go b/buffer.go
index f5e80d8..6726aaf 100644
--- a/buffer.go
+++ b/buffer.go
@@ -1,6 +1,7 @@
 package buf2d
 
 import (
+	"fmt"
 	"strings"
 )
 
@@ -30,22 +31,27 @@ func NewBuffer(width, height int) *Buffer {
 	}
 }
 
+// Set sets the rune at position (x,y) to c
 func (b *Buffer) Set(x, y int, c rune) {
 	b.data[y][x] = c
 }
 
+// Get returns the rune at position (x,y)
 func (b *Buffer) Get(x, y int) rune {
 	return b.data[y][x]
 }
 
+// Size returns width and height of b
 func (b *Buffer) Size() (w, h int) {
 	return b.width, b.height
 }
 
+// Width returns the width of b
 func (b *Buffer) Width() int {
 	return b.width
 }
 
+// Height returns the height of b
 func (b *Buffer) Height() int {
 	return b.height
 }
@@ -85,11 +91,13 @@ func (b *Buffer) Sub(x, y, w, h int) *Buffer {
 
 	// make slice references
 	data := make([][]rune, h)
-	for dy := y; dy < y+h-1; dy++ {
-		col := b.data[dy]
+	for dy := 0; dy < h; dy++ {
+		col := b.data[y+dy]
 		data[dy] = col[x : x+w]
 	}
 
+	fmt.Println(data)
+
 	// make buffer
 	return &Buffer{
 		data:   data,
diff --git a/buffer_sub_test.go b/buffer_test.go
similarity index 87%
rename from buffer_sub_test.go
rename to buffer_test.go
index df27cd1..dea498f 100644
--- a/buffer_sub_test.go
+++ b/buffer_test.go
@@ -11,6 +11,7 @@ func TestSub(t *testing.T) {
 	s := b.Sub(1, 1, b.Width()-1, b.Height()-1)
 	b.Set(5, 1, 'a')
 	s.Set(5, 5, 'b')
+	b.WriteString("Hello world", 1, 2)
 
 	fmt.Println(b)
 	fmt.Println(strings.Repeat("-", 20))
diff --git a/write_string.go b/write_string.go
new file mode 100644
index 0000000..8424846
--- /dev/null
+++ b/write_string.go
@@ -0,0 +1,15 @@
+package buf2d
+
+import "fmt"
+
+// WriteString writes a whole string to the buffer at position (x,y)
+// no word wrap is applied at all. If the string does not fit, it will be truncated
+func (b *Buffer) WriteString(str string, x, y int) {
+	for dx, r := range str {
+		if x+dx >= b.width {
+			return
+		}
+		fmt.Println(x+dx, y, string(r))
+		b.Set(x+dx, y, r)
+	}
+}