Congratulations to everyone who helped
crack this Toughnut, and correctly spotted, as Samantha has
said:
"In order for this solution to be possible, the number of matches
in each of the four groups must be consecutive."
So aj explained for 10 matches:
"for 10 matches, you can arrange them as 4,3,2,1. Take a match from
each pile from the left and add them to the pile at the end. You
end up with 3,2,1,4."
Congratulations to everyone who noticed
that in general you take from all but the smallest pile, and place
the matches on the smallest pile, as Jake and Hannah (St Peter's
School,Wrecclesham):