For this week's problem I ask you to draw a 5x5 matrix
of such a size that each of the 25 cells will accomodate either a
1p coin (here represented as a blue circle) or a 5p coin (red
circle).
The task is to place five 1p coins and three 5p coins onto the
matrix, one to a cell, such that no coin lies in a straight line -
horizontally, vertically or diagonally - as any coin of the
opposite colour.
Here is a good initial attempt that gets close - but there is no
place for the third 5p to go!
Find the solution online >>
