In[]:=
ContourPlot[Evaluate@{x+y==1,x-y==1},{x,-2,2},{y,-2,2},Axes->True,Frame->False,AxesOrigin->{1,0},AxesLabel->{"x","y"},LabelStyle->Directive[Black,12],PlotRange->{{-2,2},{-2,2}},Epilog->{Red,EdgeForm[Red],FaceForm[],Polygon[{{1+0.2,0},{1,0+0.2},{1-0.2,0},{1,0-0.2}}]}]
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