There has been a really significant amount of progress on this problem in the last year, since this article was posted. The latest experiments can be found here, from October 2021:
The technology for clearing random ash out of a region of space isn't entirely proven yet, but it's looking a lot more likely than it was a year ago, that a workable "space-cleaning" mechanism could exist in Conway's Life.
As previous comments have pointed out, it certainly wouldn't be absolutely foolproof. But it might be surprisingly reliable at clearing out large volumes of settled random ash -- which could very well enable a 99+% success rate for a Very Very Slow Huge-Smiley-Face Constructor.
There has been a really significant amount of progress on this problem in the last year, since this article was posted. The latest experiments can be found here, from October 2021:
https://conwaylife.com/forums/viewtopic.php?p=136948#p136948
The technology for clearing random ash out of a region of space isn't entirely proven yet, but it's looking a lot more likely than it was a year ago, that a workable "space-cleaning" mechanism could exist in Conway's Life.
As previous comments have pointed out, it certainly wouldn't be absolutely foolproof. But it might be surprisingly reliable at clearing out large volumes of settled random ash -- which could very well enable a 99+% success rate for a Very Very Slow Huge-Smiley-Face Constructor.