Daft Question – don’t laugh…

Er, d’you know the quadrant shapeddownward sloping components at around the bottom of the Customs House? They look like seats or some sort of pediment for carrying water away from the bottom inner corners of the buildng.

What are they for?

I can’t imagine they’re for the latter purpose as they appear on the small bridges in Venice – like on near the ‘Salute’ church.

These are probably as basic a part of architectural terminology as astragals and torus’s etc but then I’m a layman.

Thanks – john