LOL! and there I was thinking you had hand drawn every set of steps! That's a really nice symbol set you have there, then. What is it ?
And do you mean a colonnade - a bit like a cardo?
A bit like this?
I
think , though I'm not a proper historian, that they might have been generally linked to the buildings by a sort of sloping roof or an awning, so that the whole thing was like a dirty great big long communal porch over the area that I would call a pavement, and the Americans would probably call a sidewalk.
Sensible idea, really, in very hot countries - a bit of shade to dodge into on either side of the road
Weren't they also most usually found on the two main roads of the city, though?