Bongard n°4: Neutral vs Town

This is my last puzzle before the holidays, have a nice summer everyone. Here's a link to the rules of these kind of problems:

There are six boxes on the left, and another six on the right. The ones on the left conform to a pattern, or rule, that describes them, and the task of the problem-solver is to find this pattern, or rule. As an aid, the six boxes on the right do not conform to the same pattern. Sometimes they conform to a different pattern (as is the case in the above example), while in some cases the rule that describes them is simply the negation of the rule on the left. (Thus, the six boxes on the left are the ones that, somehow, have the official status of defining the pattern.)

• If that can help: (rot13) uggc://jjj.oynaxzrqvntnzrf.pbz/ebyrf/ Jul 16, 2018 at 9:00
• Since you removed both tags for trivia and knowledge, I will now assume that no knowledge about this game is required to be able to solve it. Please place them back if this assumption is wrong. Jul 17, 2018 at 15:41
• @PL457 the puzzle does not require any external sources nor specific knowledge, I provided the link to the rules in the puzzle Jul 18, 2018 at 7:57
• This is so difficult. What almost work is rot13[abg orvat noyr gb qenj na havagreehcgrq fgenvtug yvar orgjrra gur yrsgzbfg naq evtugzbfg rkgerzr cbvagf], but alas that just fails for the bottom-right one.
– Jafe
Oct 19, 2018 at 7:29
• @SilverCookies Take the leftmost rightmost points and draw a straight line between them. Here I've marked the line green if it stays inside the shape the entire way, and red otherwise: i.stack.imgur.com/z7rbL.png But again, it doesn't quite work :/
– Jafe
Nov 12, 2018 at 12:00

2 Answers

I doubt that this is the intended solution, but it does correctly partition the sets:

For each box, count the number of pixels in the silhouette (don't consider the box border) that are not white (255,255,255,255 in the png file). Then count the fraction of these pixels that are "edges", in that they are adjacent to a white pixel. If the fraction is greater than 2.6%, the figure is on the left. If less than 2.6%, it is on the right.

Intuitively,

The images on the left seem to have more edges and less fill, if you just eyeball them without looking too closely.

• That may not be the intended format of the solution, but it wouldn't surprise me at all if it were closely related to the real solution in some way. Aug 8, 2019 at 20:44
• Wrong. But good attempt. As Ben said, not too far from the actual solution. Aug 14, 2019 at 15:12

Following the hint given by @Saeidryl in comment, maybe the answer is

fictitious versus real

On the left:

apocalypse-arsonist plaguebearer necromancer nosferatu Jester werewolf

On the right

doctor townie-female spy jailor bodyguard crusader

• First guess was wrong so no longer an answer but not deleting it to help better inspire ones
– SMR
Jul 16, 2018 at 13:01
• "arbitrary" differences like the one suggested by you are forbidden in Bongard, I will add the rules to the question. You can consider it the theme of the question I guess, but it has nothing to do with the answer Jul 16, 2018 at 13:57