File:Youngdiag3-1.png

Created using Wolfram Mathematica 8 with the code:

Graphics[{Line[{{0, 0}, {3, 0}, {3, -1}, {1, -1}, {1, -2}, {0, -2}, {0, 0}}],  Line[{{1, 0}, {1, -1}}], Line[{{2, 0}, {2, -1}}], Line[{{0, -1}, {1, -1}}]}]