px = 
      x (E^(-(1/2) (Sqrt[(x^2) + (y^2)])))
py = y (E^(-(1/2) (Sqrt[(x^2) + (y^2)])))
p = px
ContourPlot[p, {x, -18, 18}, {y, -18, 18}, 
      PlotPoints -> 60]
theta = ((5 π)/180)
p = Cos[theta] px + Sin[theta] py
ContourPlot[p, {x, -18, 18}, {y, -18, 18}, 
      PlotPoints -> 60]
theta = ((90 π)/180)
p = Cos[theta] px + Sin[theta] py
ContourPlot[p, {x, -18, 18}, {y, -18, 18}, 
      PlotPoints -> 60]