This is a remix, combining two elements...

ThinkerThing's Open Board Game. Grass Surface Brick - https://www.thingiverse.com/thing:739034 for the sizing of the tile,

and "Taiwan mountain terrain 3d model" snowy.stl at https://www.thingiverse.com/thing:1771931

into what you see here.

Check out the single base that started this all, here: https://www.thingiverse.com/thing:6292937.

As mentioned elsewhere, you may choose to sand down your tiles to get them to fit inside the lip confines. They do make a satisfying POP/click sound when they do, and they won't go anywhere when snug in!