Nestlé lost the case against Cadbury-Schweppes (nowadays Mondelez) to get its Four finger chocolate crisp wafer 3-d shape registered as a trademark in the European Union.
Partly because it has not become clear that the shape in itself (so without the heavily marketed KitKat wordmark) is being perceived as a mark to indicate the commercial origin of the product. But also because Nestlé did not manage to demonstrate that the shape was recognized by the public in Belgium, Ireland, Greece and Portugal, even though they managed to demonstrate this fact in other Member States covering almost 90 % of the EU population.
This shows how difficult it is to proof that a shape mark can formally obtained (read registered) after the long and winding road of obtaining a distinctive character through use.
Not a piece of cake.