I have a spreadsheet with 14 columns and 20 rows - and what I would like is a formula that will look in a particlular row i.e B1:B14 and return and X in cell B15 if consequtive cells of 4 or more initials are found e.g. if B1:B2:B3:B4 = TT in each cell then the result in B15 would be X and if c3:c4:c5:c6 = MM the result in B16 would be X. If however B1:B2:B3 = TT and B4 = NN then no X is returned (cells will either contain initials or be blank)

is this possible?