my old collection, I ordered some new ones from Pick-A-Brick. I realized that the color was different - the new grey bricks, on the left, make the old ones on the right look even older and dirtier than they are. According to Brickipedia, this new color, bley, has some blue in it and replaced the old one in 2004. A pity, since the old grey bricks are among the most stylish objects I know.
UPDATE. Fascinated by this shape, I made a painting of it.