+A row of five black square tiles is to have a number of its tiles replaced with

+coloured oblong tiles chosen from red (length two), green (length three), or

+If red tiles are chosen there are exactly seven ways this can be done.

+If green tiles are chosen there are three ways.

+And if blue tiles are chosen there are two ways.

+Assuming that colours cannot be mixed there are 7 + 3 + 2 = 12 ways of

+replacing the black tiles in a row measuring five units in length.

+How many different ways can the black tiles in a row measuring fifty units in

+length be replaced if colours cannot be mixed and at least one coloured tile

+NOTE: This is related to problem 117.

+use Math::GMP qw(:constant);

+ my ($tile_len, $total_len) = @_;

+ foreach my $len (0 .. $tile_len-1)

+ for my $len ($tile_len .. $total_len)

+ push @counts, $counts[-$tile_len]+$counts[-1];

+ # We need to exclude the all-black-squares one which is:

+ # 2. Should not be included.

+ return count(2, $total_len) + count(3, $total_len) + count(4, $total_len);

+print count_for_234(50), "\n";