ABAQUS periodic

For simplicity in understanding Perioidic BC in ABAQUS, I am trying to implement in a single element elastic model.

Material is elastic. There are two reference points defined Refpoint 1 for x-direction pull and Refpoint 2 for y-direction pull. Please find the attached picture for clarity in the model.

I have defined the equations for PBC in ABAQUS as below:

x1-x2+Refpoint1=0

y1-y2+Refpoint1=0

x3-x4+Refpoint1=0

y3-y4+Refpoint1=0

x2-x3+Refpoint2=0

y2-y3+Refpoint2=0