13 Apr
2000
13 Apr
'00
6:45 a.m.
"Scott F. Hall" wrote:
Anyone have a good explanation of the mechanism involved in that Dr. Nim
game and how it works? Are there any springs/rubber bands or do those
pivotable pieces just rock freely? Looks like Dr. Nim might be an easy
one to reproduce from scratch, but only if I can get more info on it.
A 1968 book, "Game Playing with Computers" by Donald D. Spencer has a good
description of the logic behind the game. The basic secret of winning is to
always present your opponent with an even position. To determine an odd or
even position, convert the number of coins in each row to binary, i.e.:
5 Pennies 101
4 Nickels 100
3 Dimes 011
Add the columns. An even position is described if *each* column adds up to
zero or an even number; otherwise the position is odd. In the above case, it
is an odd position. The left column is even (1+1+0), the second column is
odd (0+0+1) and the third column is even (1+0+1).
The exercise of converting the above explaination to a mechanical device is
left as an exercise for the reader :).