Four of these boards show the same shape made of four cells, turned or flipped over and placed anywhere. Which board shows a different shape?

Boards (a), (b), (c) and (e) all show an L-shape: a line of three cells with one extra cell at the end of the line, turned or flipped. Board (d) has its extra cell next to the MIDDLE of the line of three, making a T-shape, which no turn or flip of the L can give. So (d) is the odd one out.