No, Poorman, the block of glass is solid.
I suppose that they can focus the laser to any given point.
They say: "New laser technology is used to etch very fine dots inside a cube of glass to create visually stunning images. A light source can be added to increase the effect."
(might save up for one of them there light boxes )

I guess that they use some kind of CNC programming (CNC:ComputerisedNumericControl), like they do for punching out holes in a sheet of steel.
Where I used to work, they had a CNC Punch machine that was capable of punching 600 holes per minute - sounded like a machine gun going off lol.
It could handle a piece of steel that measured 2Mtrs sq (8ftx8ft(approx)), and punch out holes of differing sizes in a matter of seconds!
There was a turret in the middle that housed all the punches, and that would spin to the correct punch-size, at the correct X-Y axis...all at terrific speed.
Was very impressive to watch...but very boring to work.
All the operator had to do was load up a piece of steel, press a button *bang bang bang*, unload the steel, then load another one...repeat 500times a day..grrr...

that's why I went back to truck driving lmaooo