The Five Pennies

by Henry E. Dudeney

It is quite easy to place four pennies in such a way that each penny touches every other one. Just place three of them on the table in the form of a triangle so that they touch one another, and then lay the fourth penny on top of this triangle - as shown on the far left.

Now add one more penny and try to do the same thing with five pennies - again every penny has to touch every other penny.