[mikhailfranco]

For the third I got:

triangle never in circle - circle never in triangle

compared to the given answer:

triangle bigger than circle - circle bigger than triangle

My solution is more general (worse), because it ignores size in non-containment arrangements, but also slightly more specific (better), because it constrains the single containment example in each set.

Neither of the rules say anything about overlapping cases, but there are no overlapping examples in the given sets. So there is a underlying constraint of no overlaps, but it applies to both sides, so it is not a distinguishing factor.

[CRConrad]

The idea is to arrive at a rule you can use for any given picture, to decide if it goes on the left or right:

> In a Bongard problem, you have to figure out what the rule is. You are given twelve specific images, and the result of applying the rule to each. (The rule assigns an image to either the left or right group.) Once you have discovered the rule, applying it to new images would be trivial.

Your rules don't do that. Most of the pictures have neither "triangle in circle" nor "circle in triangle", so your rules don't apply to... Ten out of the twelve pictures.

[laszlokorte]

The issue with your solution is that it can not decide for a single combination of circle and triangle if it would belong to the left or the right side.

[EE84M3i]

>The contents of the six boxes on the left all have something in common. The six on right also all have something in common, which is the opposite of the ones on the left.

I think you and the author might disagree on the meaning of "opposite" here. I think they mean logical negation and you are using a more colloquial interpretation.

[teknopaul]

There is no correct answer (see nebulosity) , the point is to learn how the problem works. And what a marvelous thing your brain is by being able to come up with any solution.