Ventilation Chimneys on Barn

I always have an eye open for a pattern photograph. This isn’t a great subject, but I thought the shape and angle we worth capturing, specifically with a view to converting to monochrome / black and white. These six chimneys are on the roof of a barn that I believe housed a large herd of cows. The sky was actually blue rather that grey, but with the texture of the roof tiles and the metal chimneys I thought it would be better without any colour in the final edit.