diff --git a/Makefile b/Makefile
index acc023319..096f76626 100644
--- a/Makefile
+++ b/Makefile
@@ -46,7 +46,7 @@ CXXFLAGS = -std=c++11 -fno-exceptions -fno-unwind-tables -fno-rtti -nostdlib
 products := boot.elf boot.hex boot.bin
 
 objs += external/freertos/tasks.o external/freertos/list.o external/freertos/queue.o external/freertos/portable/GCC/ARM_CM4F/port.o external/freertos/portable/MemMang/heap_1.o
-objs += external/newlib/libc/string/memset.o external/newlib/libc/string/memcpy.o
+objs += $(addprefix external/newlib/libc/, string/memset.o string/memcpy.o string/strlen.o)
 
 objs += lib/assert.o
 
diff --git a/external/NEWLIB.txt b/external/NEWLIB.txt
index b84900a08..cfe83cffd 100644
--- a/external/NEWLIB.txt
+++ b/external/NEWLIB.txt
@@ -1,3 +1,4 @@
 - Using memcpy and memset
 - using <string.h>, <stdlib.h>, and <stdint.h>
 - using <stdbool.h> for "bool"
+- using strlen from <string.h>
diff --git a/kandinsky/include/kandinsky/rect.h b/kandinsky/include/kandinsky/rect.h
index 91be83501..9c6ed5d09 100644
--- a/kandinsky/include/kandinsky/rect.h
+++ b/kandinsky/include/kandinsky/rect.h
@@ -17,7 +17,7 @@ typedef struct {
       KDCoordinate width;
       KDCoordinate height;
     };
-    KDPoint size;
+    KDSize size;
   };
 } KDRect;
 
diff --git a/kandinsky/include/kandinsky/text.h b/kandinsky/include/kandinsky/text.h
index 78292601d..4077d0637 100644
--- a/kandinsky/include/kandinsky/text.h
+++ b/kandinsky/include/kandinsky/text.h
@@ -5,5 +5,6 @@
 
 void KDDrawChar(char character, KDPoint p);
 void KDDrawString(char * text, KDPoint p);
+KDSize KDStringSize(char * text);
 
 #endif
diff --git a/kandinsky/src/line.c b/kandinsky/src/line.c
index 32a721197..6312a7a61 100644
--- a/kandinsky/src/line.c
+++ b/kandinsky/src/line.c
@@ -3,6 +3,6 @@
 
 void KDDrawLine(KDPoint p1, KDPoint p2) {
   for (KDCoordinate x = p1.x; x<p2.x; x++) {
-    PIXEL(x, p1.y) = 0xC7;
+    PIXEL(x, p1.y) = 0xFF;
   }
 }
diff --git a/kandinsky/src/text.c b/kandinsky/src/text.c
index ff3aa9e05..b7f573c2e 100644
--- a/kandinsky/src/text.c
+++ b/kandinsky/src/text.c
@@ -1,11 +1,12 @@
 #include <kandinsky/text.h>
 #include <framebuffer.h>
+#include <string.h>
 #include "font.h"
 
 void KDDrawChar(char character, KDPoint p) {
   for (int j=0; j<BITMAP_FONT_CHARACTER_HEIGHT;j++) {
     for (int i=0; i<BITMAP_FONT_CHARACTER_WIDTH;i++) {
-      PIXEL(p.x+i, p.y+j) = bitmapFont[character-BITMAP_FONT_FIRST_CHARACTER][j][i];
+      PIXEL(p.x+i, p.y+j) = 0xFF-bitmapFont[character-BITMAP_FONT_FIRST_CHARACTER][j][i];
     }
   }
 }
@@ -19,3 +20,10 @@ void KDDrawString(char * text, KDPoint p) {
     position.x += BITMAP_FONT_CHARACTER_WIDTH;
   }
 }
+
+KDSize KDStringSize(char * text) {
+  return (KDSize){
+    .width = strlen(text)*BITMAP_FONT_CHARACTER_WIDTH,
+    .height = BITMAP_FONT_CHARACTER_HEIGHT
+  };
+}
diff --git a/poincare/include/poincare/number.h b/poincare/include/poincare/number.h
index eb9f9b50b..d80bcba59 100644
--- a/poincare/include/poincare/number.h
+++ b/poincare/include/poincare/number.h
@@ -11,6 +11,7 @@ class Number : public Expression {
     virtual void layout();
   private:
     int m_value;
+    char m_stringValue[16];
 };
 
 #endif
diff --git a/poincare/src/number.cpp b/poincare/src/number.cpp
index bd5ebac21..9f8d0e03f 100644
--- a/poincare/src/number.cpp
+++ b/poincare/src/number.cpp
@@ -1,13 +1,26 @@
 #include <poincare/number.h>
+#include <kandinsky/text.h>
 
 Number::Number(int v) : m_value(v) {
+  for (int i=0; i<16; i++) {
+    m_stringValue[i] = 0;
+  }
+
+  int value = v;
+  for (int i=0; i<15; i++) {
+    int digit = value - 10*(value/10);
+    m_stringValue[i] = '0' + digit;
+    value = value/10;
+    if (value == 0) {
+      break;
+    }
+  }
 }
 
 void Number::layout() {
-  m_frame.width = 20;
-  m_frame.height = 10;
+  m_frame.size = KDStringSize(m_stringValue);
 }
 
 void Number::draw() {
-  KDFillRect(m_frame, 0x7F);
+  KDDrawString(m_stringValue, m_frame.origin);
 }
diff --git a/src/hello.cpp b/src/hello.cpp
new file mode 100644
index 000000000..de1ffc538
--- /dev/null
+++ b/src/hello.cpp
@@ -0,0 +1,32 @@
+extern "C" {
+#include "hello.h"
+#include <kandinsky.h>
+}
+
+#include <poincare.h>
+
+void hello() {
+  KDFillRect((KDRect){
+      .x = 0,
+      .y = 0,
+      .width = 240,
+      .height = 320},
+      0x00);
+  /*
+  for (int i=0; i <255; i++) {
+    KDFillRect((KDRect){.x = (KDCoordinate)i, .y = (KDCoordinate)i, .width = 100, .height = 200}, i);
+  }
+  KDDrawString("Hello, world", (KDPoint){});
+  */
+
+  Number n1 = Number(123);
+  Number n2 = Number(45);
+
+  Fraction f = Fraction(&n1, &n2);
+
+  f.layout();
+  f.m_frame.origin = (KDPoint){.x = 0, .y = 0};
+  f.draw();//(KDPoint){.x = 10, .y = 10});
+
+
+}
diff --git a/src/hello.h b/src/hello.h
new file mode 100644
index 000000000..9bb085a0d
--- /dev/null
+++ b/src/hello.h
@@ -0,0 +1 @@
+void hello();