Mailing List Archive: 49091 messages

## [REBOL] Re: Another coffee break problem?

### From: tomc:darkwing:uoregon at: 13-Nov-2003 10:30

```
On Wed, 12 Nov 2003, Tom Conlin wrote:

> On Tue, 11 Nov 2003, Joel Neely wrote:
>
> >
> > Hi, Gregg,
> >
> > Gregg Irwin wrote:
> > >
> > > JN> The following 3-by-3 display is a simple magic square:
> > >
> > > JN>          0  8  4
> > > JN>          5  1  6
> > > JN>          7  3  2
> > >
> > > JN> because each row and each column sums to 12...
> > >
> > > No diagonals? I thought magic squares had to work on the diagonal as
> > > well? (not to be nit-picky or anything :)
> > >
> >
> > To be equally picky ;-)
> >
> > That's why I said "simple magic" square instead of "totally magic".  I
> > was going to post a follow-up problem to refine the first program so
> > that it also checks diagonals.
> >
> > Also, not all sources I've looked at insist on diagonal operations.  One
> > interesting way to generalize the problem is to "magic" rectangles with
> > different height and width.  In that case, the definition of "diagonal"
> > becomes more interesting...
> >
> > -jn-
>

I did wake up in in the middle of the night remembering I had
only coverd a third of the cases. and it looks like I should not have
those dups in there ...

pprint b 3              ; normal
pprint flip b 3 3       ; about vertical axis
pprint reflect b 3 3    ; rotate left 90
flip b 3 3       ; back to normal
pprint reflect b 3 3    ; about backslash
b: head reverse b
pprint b 3              ; rotated 180 degrees
pprint flip b 3 3       ; about horizontal axis
pprint reflect b 3 3    ; rotate right 90
flip b 3 3       ; back to 180
pprint reflect b 3 3    ; about slash

but still have to handle the other 16 cases
```