How did they achieve this continuous multi-level laser etching of a SS tumber?

[Doug Fisher]

I am curious about the technique used to achieve "continuous" image etching like in the following examples of laser etched powder coated SS tumblers. The images appear to stay proportionally correct and relatively detailed (e.g the rifle in the white example below), even through the area of steep reduction in circumference. A long lens like a 4", raising the bottom of the tumbler in the rotary to achieve level from top to bottom, and intentional distortion of the graphic to match the reduction in circumference between the top of the tumbler and the bottom of the tumbler?

Two Level Engrave 3.JPG

Two Level Engrave 2.JPG

Two Level Engrave 1.JPG