Our house was the second one built in the new subdivision. Now they are building stabilizing walls on the lots near the house. There is a steep grade here, and they have to reinforce it against earthquakes.
This type of work is used to make three-dimensional structures, such as columns and the footing.
The column of reinforcement you saw them building in the other photo is on the bottom to provide the footing. The vertical bars will go inside the concrete blocks.
These provide power to the cement mixer. I have often said it's a wonder Ticos aren't all dead of electrocution
This is the final step. They lay the blocks and then fill in the holes in the blocks. This, with all the reinforcement, makes for a strong wall. I was impressed with their work, but visually they were sloppy.