"The third dimension won’t be orthogonal." Are you sure? In a 3-D coordinate system all axes are orthogonal because they make 90 degrees angles with each other

"The third dimension won’t be orthogonal." Are you sure? In a 3-D coordinate system all axes are orthogonal because they make 90 degrees angles with each other. Edit: I see that you mean "cannot be drawn as orthogonal lines on paper." But, in reality they are orthogonal e.g., when I construct a 3-D model of a cube.