We start with one yellow cube and build around it to make a 3x3x3
cube with red cubes. Then we build around that red cube with blue
cubes and so on. How many cubes of each colour have we used?
Complete the magic square using the numbers 1 to 25 once each. Each
row, column and diagonal adds up to 65.
I have forgotten the number of the combination of the lock on my
briefcase. I did have a method for remembering it...