The Ace of Diamonds Gang (first one)
The Symbols , which the author used stand diresctly for the boys' idea of a wild and rule less gang that can't be stopped by physical power and the reality which the boys so wanted to get rid of.
If you look closer to the name you'll notice straight away that it stands for their unreachableness. The Ace is a Symbol for power and strenght, which should show their enemies that any obstacle is ridicules senseless, because you can't stem against something that has nand shows no weak point. The diamond symbolises the richness and pureness of the boys' idea of the gang. It's quite interesting that they want to show others how untouchable the diamond is, but not either the gang's members can reach it. So they are kind of prophets of their idea, which they so want to own, but can't because it  is somehting unreachable. To hide that fact they try to make it seem pointless to even think about a weak point in the Ace of Diamonds Gang.
In a totally contrast stands the library card, which the narrator leaves behind by a mistake where they watched Jorgesson. It shows that the gang's members are normal school-kids in real. All the weakness and normality is packed into this card. When you read the story the Ace of Diamonds Gang becomes weaker and more ridicules and the library card is the finishing aspect.
So there are those two symbols which stand for idea and the opposite reality. The story shows that you can't escape your real life because one day or just caused by an unlucky situation reality will catch you up.

The Ace of Diamonds Gang (final one)

The Symbols, which the author used stand directly for the boys' idea of a wild and rule less gang that can't be stopped by physical power and the reality which the boys so wanted to get rid of. 

The Gang meant more than just boys who play a trick and have a great laugh. "Like the heroes of history it arose when it needed to be there". Here you can see how serious he took the fortune of the gang and he saw it as a kind of a bailout to save the day. I think he saw them in a light of glory who's doings are grateful. That's also why he used a lot of military language, to show the organized and irreversible determination of the Gang. He shows that it was the best thing that ever happened to him and he used it to escape the boredom of his boyhood. Maybe his ordinary life is not as he wanted it to be and so he thinks back to the times when life actually was just as he always wanted it to be like.
If you look closer to the name you'll notice straight away that it stands for their unreachableness. The Ace is a Symbol for power and strenght, which should show their enemies that any obstacle is ridicules senseless, because you can't stem against something that has nand shows no weak point. The diamond symbolises the richness and pureness of the boys' idea of the gang. It's quite interesting that they want to show others how untouchable the diamond is, but not either the gang's members can reach it. So they are kind of prophets of their idea, which they so want to own, but can't because it  is somehting unreachable. To hide that fact they try to make it seem pointless to even think about a weak point in the Ace of Diamonds Gang.
In a totally contrast stands the library card, which the narrator leaves behind by a mistake where they watched Jorgesson. The library card causes te downfall and in conclusion the end of the Ace of Diamonds Gang. It shows that the gang's members are normal school-kids in real. All the weakness and normality is packed into this card. It turns out that they are definitely not the heroes as they said they'd were. All their dreams, hopes and fantasy got destroyed by a card which shows how embarrassing childish their idea of escape was. No heroes would be signed up in a library an that makes us see how difficult and how much effort it actually needs to be a "hero", but to make up one seems easier even if you somewhere in your mind know that it can't be that easy you still try to live that life, just because you are even a bit afraid of your proper life, because it's too normal and you are scared to be only one out of 6 billion rather than one out of a handful of heroes.  When you read the story the Ace of Diamonds Gang becomes weaker and more ridicules and the library card is the finishing aspect.
So there are those two symbols which stand for idea and the opposite reality. The story shows that you can't escape your real life because one day or just caused by an unlucky situation reality will catch you up.