GLfloat coord = 40;
int grid = 10;
glLineWidth(10);
glNormal3f(0, 1, 0);
glBegin(GL_LINES);
glColor3f(1, 0, 0);
// glNormal3f();
glVertex3f(-coord, -coord, -coord);
glVertex3f(coord, -coord, -coord);
glColor3f(0, 1, 0);
glVertex3f(-coord, -coord, -coord);
glVertex3f(-coord, coord, -coord);
glColor3f(0, 0, 1);
glVertex3f(-coord, -coord, -coord);
glVertex3f(-coord, -coord, coord);
glColor3f(1, 1, 1);
glEnd();
glLineWidth(1);
glBegin(GL_LINES);
for (int i = 0; i <= grid; i++)
{
  glVertex3f(-coord, -coord, (i / (float)grid) * 2 * coord - coord);
  glVertex3f(coord, -coord, (i / (float)grid) * 2 * coord - coord);
}

for (int i = 0; i <= grid; i++)
{
  glVertex3f((i / (float)grid) * 2 * coord - coord, -coord, -coord);
  glVertex3f((i / (float)grid) * 2 * coord - coord, -coord, coord);
}
glEnd();