Albedo's elegant solution
Hey, I didn't say that!
In fact, it's not mine, but I did recognize the beauty of it and remembered it (added it to the wiki, too!)
Walls don't support constructions diagonally, though, and grates don't support grates. So it's a 50/50 ratio underneath. Like I said before.
I'm glad you understand the problem - now we all do. But you still don't seem to understand the solution - I'll try to make it easier to see, because it's simply
not limited to 1 grate/support (which is what a 50/50 would be).
A wall below can support 4 grates, so that's where we start:
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#+#
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If you have a 2nd wall below, some of the grates attached to that can be tucked in so they are diagonal to the first wall or next to other grates, but are still supported just fine by the 2nd wall...
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#+#
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#+# #Now, each of those are perfectly supported, right? And we still have our 4:1 ratio.
And we can expand infinitely on that, continuing the 4:1 ratio (or close to, depending on the edges), so it stays ~80% grate, 20% wall support below.
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#+##
#+###+#
###+#
###+## ##
#+###
#+##
##+# +####+####+#
####+# ##+# #
#+# Count across any row - 4 grates/1 support, repeatable infinitely. Each grate is attached to one support, 4 grates/support.
Like I said before.
If there are walls or floors surrounding this pattern on the level we're working on, those gaps in the edges can be filled in, supported from there, moving the ratio back closer to a true 4:1.