I finally located the photos I have been searching for since February!
The more common (or at least the ones I saw most often) examples of the piere/pietre sbuse look like this:
The ones I wanted to show you are oriented like this:
And, I was so lucky to find an example of how they may have been used in the past, and certainly are utilised in the present:
My original post about these architectural features can be found here: https://ytaba36.wordpress.com/2012/02/23/pietre-sbusepiere-sbuse-another-mystery-in-venice/