Some nested cubes based on some web art. includes scad and stl files.

only advanced makers can have some idea of getting them into filament, you may have to make wth variable higher.

here is the final scad code, set the rotation to the number you want, change the width, use more cubes, and after is the first version:

wth = 1.5;//width of bars
rtn = 90/17;//can be used as rotation
xt = 2;//spacing
for(h = [1 : 23])
{
rotate([h*4,0,h*4])
difference(){
wth = 1.5+3/h;//solidify size mod
cube(size = [xt*h,xt*h,xt*h], center = true);

     cube(size = [xt*h,xt*h-wth,xt*h-wth], center = true);
     cube(size = [xt*h-wth,xt*h,xt*h-wth], center = true);
     cube(size = [xt*h-wth,xt*h-wth,xt*h], center = true);
}
}
___________________________

easier version:

  wth = 1.1;//width of bars
 for(h = [0 : 17])
  { 
      rotate([h*5,0,0])
   difference(){
 
      cube(size = [h,h,h], center = true);
 
     cube(size = [h,h-wth,h-wth], center = true);
     cube(size = [h-wth,h,h-wth], center = true);
     cube(size = [h-wth,h-wth,h], center = true);
 
    } 
  }