Creating repeating negative extrusions?

How to create repeated negative extrusions as such?

It’s basically the same question you asked here

Create that, and cut it out of a box with BooleanDifference.

Did you go through the basics (eg Rhino level 1 training?)

herefor you also can use boss, you need the outlines first by offset for instance if you create it from scratch then place each outline away from the surface, i use gumball to make the distances which keeps the values, so i select all click on an arrow then deselect one outline and move the rest and so on. then select all outlines at once and use boss using the surface of course as the boundary.