Solving Tic-Tac-Toe

Well-known that it's a draw.

Analyze solution
(can do as a kid! I think I did.)

looking 0,1,2 moves ahead
[move to win; block a win; fork!]

a clever trick that works on some naive players:
(who are only familiar with "start in center")
O X
 O
X
[example used in Connect Four thesis]

exhaustion;
prune via symmetry & other techniques

(many cases forced; tricky are
O
 X
  X

OX
 X

Can do some pruning of "dumb moves".
)
