The suggested conditional didn't perform as hoped, as I had made exactly that attempt. I changed it to == to see what would happen. The result was the inverse of my objective, which was promising. It created the nine pins in the appropriate locations. A bit more experimenting and this works:
if (! ( (col_counter % 4 == 0) && (row_counter % 4 == 0 ) ) )

Thanks for the assistance!

On Wednesday, December 28, 2022 at 07:03:20 PM EST, Michael Möller <private2michael@gmail.com> wrote:  

I'd just let the for loops produce the whole grid and put the "if" in the innermost place. It would then sayif ( (col_counter % 4 != 0) && (row_counter % 4 != 0 ) ) 
Msquare

After seeing DeMorgan's Laws, I realize that this is something I once knew, again, back in my high school days, but those bytes have been lost to the extreme birthdays behind me.  I suppose since they are equivalent, having accomplished this much has been satisfying.
If it wasn't for the necessity of a taper, I'd have been able to SVG this entire project. Even now, if the alignment isn't correct, I'll start with an SVG and difference shorter cylinders without the taper in every location. As long as it doesn't reach z = 0, the effective result is acceptable.
It's certainly been a fun learning experience, which is part of the reason I use (and occasionally struggle with) OpenSCAD. This would have been a fun high school or college course, to be sure.

On Friday, December 30, 2022 at 05:11:47 PM EST, Hans L <thehans@gmail.com> wrote:  

The conditional that Douglas Miller suggests is logically equivalent due to "De Morgan's Laws" by the way:https://en.wikipedia.org/wiki/De_Morgan%27s_laws

On Fri, Dec 30, 2022 at 8:05 AM Douglas Miller doug@milmac.com wrote:

This is a trifle simpler, and (to me, at least) more clear:

    if ( (col_counter % 4 != 0) || (row_counter % 4 != 0) )

The opposite of (a AND b) is not (NOT a) AND (NOT b): it's (NOT a) OR (NOT b), and that's why the suggested

    if ( (col_counter % 4 != 0) && (row_counter % 4 != 0 ) )

doesn't work, and
   
    if ( (col_counter % 4 != 0) || (row_counter % 4 != 0) )

will.

On 12/29/2022 6:38 AM, fred wrote:

The suggested conditional didn't perform as hoped, as I had made exactly that attempt. I changed it to == to see what would happen. The result was the inverse of my objective, which was promising. It created the nine pins in the appropriate locations. A bit more experimenting and this works:
if (! ( (col_counter % 4 == 0) && (row_counter % 4 == 0 ) ) )

Thanks for the assistance!

  On Wednesday, December 28, 2022 at 07:03:20 PM EST, Michael Möller <private2michael@gmail.com> wrote:  

 I'd just let the for loops produce the whole grid and put the "if" in the innermost place. It would then say if ( (col_counter % 4 != 0) && (row_counter % 4 != 0 ) )  

Msquare

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