In Greenwich Village, tic-tac-toe is played in an atypical way. At each turn a player marks as many squares as he wishes provided they are in the same vertical or horizontal row (they need not be adjacent). The winner is the one who marks the last square.

Which player has the advantage, and what strategy should he employ?

The local weatherman says No Rain, and his record is 2/3 accuracy of prediction. But the Federal Meteorological Service predicts rain, and their record is 3/4.

With no other data available, what is the chance of rain?

To protect his country a king decided to build a wall made out of stone along the border. The wall had to be 3 meters thick and 5 meters high. The border of the country has a length of 500 kilometers. Assuming that one cubic meter of stone weights about 3000 kg, how much heavier becomes the earth by building this wall?