These guys were hard at work unloading cement and terra cotta flooring blocks by hand when I came by, and what caught my ear was the laughter that accompanied the sort of xylophone-like clinking tones made by the stones as they were set down onto the growing stacks on the sidewalk.
I have no idea what it was they were laughing about as they went about their work; maybe something they'd seen on TV the night before, maybe an off-color joke, who knows? They kept the patter going as they worked steadily and with a level of energy I'd be surprised if they carried through the afternoon, but again, who knows?
When I came back five minutes later with a bag containing eight bottles of orange juice from a nearby cart vendor and set it down on a stack of stones for them they returned my smile and thanked me, and I went on my way.
An hour later when I was heading back the truck was gone and I suspect they'd gone back for another load. I'd intended to come back later that day to see if they were still at it (this was at a sizable construction site that would undoubtedly need many truckloads of stones) but I didn't make it.