addGLObject(
            GL.GL_LINES,
            // vertices
            FloatBuffer.wrap(new float[] {
                // x axis
                -20.0f, 0.0f, 0.0f, 1.0f,
                 20.0f, 0.0f, 0.0f, 1.0f,
                // y axis
                 0.0f, -20.0f, 0.0f, 1.0f,
                 0.0f,  20.0f, 0.0f, 1.0f,
                // z axis
                 0.0f, 0.0f, -20.0f, 1.0f,
                 0.0f, 0.0f,  20.0f, 1.0f
            }),
            // colors
            FloatBuffer.wrap(new float[] {
                1.0f, 0.5f, 1.0f, 0.0f,
                222.0f, 0.0f, 0.0f, 1.0f,
                0.5f, 1.0f, 0.5f, 0.0f,
                0.0f, 0.0f, 0.0f, 50.0f,
                1.0f, 1.0f, 0.5f, 0.0f,
                0.0f, 0.0f, 0.0f, 100.0f
            })
        );