what's the rule for phase differences on a stationary wave? [A-level physics]

so if you have a diagram with two points on the same stationary wave, how do you know if they are in phase, out of phase or anti phase?

Am I right in thinking that if they are on the same "half" of the wavelength, then they are in anti phase??

if they are both between two nodes, they are in phase. If they are on opposite sides of a node, they will be in antiphase (180 degrees out of phase)

So if they are on the same half of the wavelength, they would be in phase.

thanks! So is this now right?

i) Points on the same arc (between the same nodes) --> in phase
ii) Points on opposite arcs (one positive displacement, other negative) --> anti-phase
iii) It doesn't matter where in the arc the points are located, they are always either in phase or anti-phase (i.e. there's no in-between)