1 hour ago, zztong said:A blocks is as equally supported as the block below them, vertically. Or, if there is air below them, then their support is slightly weaker than the strongest block beside them. That horizontal support weakens the farther out you go horizontally without any vertical support.
It also "weakens" with vertical distance, just less so than with horizontal (given no bedrock connection).
The "show stability" seems to ignore that, but here's a quick test I did:
The point here is, the left and the right pillar will collapse if you add one more (all 8 side-attached blocks drop + the added one). The middle one obviously doesn't - didn't test yet how many it would actually require to collapse that.
And the "show stability" shows NO difference. It's .. not all that reliable 😛
EDIT: Went on to test it .. adding wood to the side of the middle pillar caused all the wood to collapse after 7 more blocks. But it also collapsed on a way shorter tower on a re-try, after the same 7 side-attached wood blocks. The actual SI is weird (prolly stacking wood on top of iron/steel is going past the calc distance for SI, and it just assumes there's bedrock below beyond some point, or something to that effect, I haf no actual clue..)