I try to add coordinate system to en.wikibooks.org/wiki/OpenGL_Programming/Scientific_OpenGL_Tutorial_05

First I tried to draw some additional points to see the difference :
// 3 points in homogeneous coordinates
GLfloat coo[3][4]
// in init function
glBindBuffer(GL_ARRAY_BUFFER, vbo[3]);
glBufferData(GL_ARRAY_BUFFER, sizeof coo,coo, GL_STATIC_DRAW);
// in display function :
glBindBuffer(GL_ARRAY_BUFFER, vbo[3]);
glDrawArrays( GL_LINES, 0, 3);

But nothing happens

Finally, I would like to get something i.imgur.com/GVNjFqX.jpg

Thanks in advance