Constructing Mortared Natural Stone Pillars

What happens here

The construction of the custom stone pillars is shown. Workers are carefully laying and mortaring natural stone blocks around the existing wooden pergola posts. Each pillar is being built up to a certain height, and a large, flat, light-colored capstone is observed on top of the finished stone work, with a central cutout designed to fit snugly around the wooden post.

Goal: Build custom natural stone pillars around the pergola posts using mortar.