Why do I have this strong feeling that blockladder is an alt of someone here? The owner never log back in to the blockladder account since January 12, 2019 and as mentioned here that the other 3 posts he/she made was made 3 years ago. So It must be an alt account and the guy behind is just lurking somewhere. Maybe if we get to figure his alt, he might give us another hint for this.

Here are the posting dates of blockladder: (oldest to newest)
December 10, 2015, 10:44:52 AM
December 10, 2015, 11:21:18 AM
December 10, 2015, 06:07:06 PM
December 28, 2015, 03:47:08 PM (deleted post)
January 12, 2019, 10:33:13 AM

If you look at it. He/She intentionally used this account to post about the puzzle and then just vanish.