Notebook not found
The Mathematica notebook /notebooks/PointLattices/Tetromino.nb was not found.
It is possible that the notebook has been renamed or relocated, so please check the MathWorld site for the entry corresponding to the notebook you wanted and follow the notebook link there. If that link leads you back to this page, please check again in a few days and the problem will most likely have been resolved.
Best regards,
MathWorld Webmaster