- 08 Jul '11 22:56 / 1 edit(thanks to the New Scientist Magazine)

I have a standard set of 28 dominos. I take some and arrange them into a rectangle. The rectangle has the property that no horizontal or vertical straight line can be drawn across it, which doesn't bisect at least one domino. I take this rectangle apart, add two more dominos and make another rectangle with the same property. How many dominos are in my second rectangle? - 08 Jul '11 23:52 / 2 editsThe line must be horitontal or vertical and start and finish outside the rectangle.

For instance

||=

=||

(where || is a vertical domino, and = is a horizontal domino)

... cannot be one of my rectangles because it can be divided neatly by both a horizontal cut:

||=

.....

=||

and a vertical one:

|| . =

= . ||