  The game of nim, with its simple rules, its elegant solution and its
historical importance is the quintessence of a combinatorial game, which is why
it led to so many generalizations and modifications. We present a modification
with a new spin: building nim. With given finite numbers of tokens and stacks,
this two-player game is played in two stages (thus belonging to the same family
of games as e.g. nine-men's morris): first building, where players alternate to
put one token on one of the, initially empty, stacks until all tokens have been
used. Then, the players play nim. Of course, because the solution for the game
of nim is known, the goal of the player who starts nim play is a placement of
the tokens so that the Nim-sum of the stack heights at the end of building is
different from 0. This game is trivial if the total number of tokens is odd as
the Nim-sum could never be 0, or if both the number of tokens and the number of
stacks are even, since a simple mimicking strategy results in a Nim-sum of 0
after each of the second player's moves. We present the solution for this game
for some non-trivial cases and state a general conjecture.
