(*Kilka funkcji falowych dla czastki w pudle kwadratowym 
o boku L .  
          Liczby calkowite nx i ny sa liczbami kwantowymi*) 
L = 10. 
nx = 1
ny = 1
ContourPlot[
      Sin[((nx π x)/L)] Sin[((ny π y)/L)], {x, 0, 10}, {y, 0, 
        10}, PlotPoints -> 25]
nx = 1
ny = 2
ContourPlot[
      Sin[((nx π x)/L)] Sin[((ny π y)/L)], {x, 0, 10}, {y, 0, 
        10}, PlotPoints -> 25]
nx = 2
ny = 1
ContourPlot[
      Sin[((nx π x)/L)] Sin[((ny π y)/L)], {x, 0, 10}, {y, 0, 
        10}, PlotPoints -> 25]
nx = 2
ny = 2
ContourPlot[
      Sin[((nx π x)/L)] Sin[((ny π y)/L)], {x, 0, 10}, {y, 0, 
        10}, PlotPoints -> 25]
nx = 4
ny = 4
ContourPlot[
      Sin[((nx π x)/L)] Sin[((ny π y)/L)], {x, 0, 10}, {y, 0, 
        10}, PlotPoints -> 25]