Use the 'double-3 down' dominoes to make a square so that each side has eight dots.
Use these four dominoes to make a square that has the same number of dots on each side.
Arrange the digits 1, 1, 2, 2, 3 and 3 so that between the two 1's
there is one digit, between the two 2's there are two digits, and
between the two 3's there are three digits.
This problem is taken from the UKMT Mathematical Challenges.