Building a border line

so i saw this epic line border and i wonder if its a GUI or blocks if blocks what metarial?
picture:

For me it’s a interface graphique

a surface gui? or is it something else

But for me it’s a in surface. I’m not really sure

but if u look at it on the side its gonna be flat (if its a surface gui)

I believe that’s a SelectionBox if you’re talking about the white lines. Once you add the SelectionBox you can go under Properties > Data > Adornee and pick the part you want it to go around.

It looks like a selection box and you can change the colour of the selection box to anything you want. The walls look like glass

Pretty sure thats it’s a SelectionBox and a transparent brick.