Suggestion: more puzzle themes

[Arihol]

I think “Greek gift” is a recurring theme that should be an independent category. It’s a very thematic sacrifice, and you see it in two types of situations:

• you are the attacker
• As the defender, you have to decide if you can take the bishop and defend against the attack or you can’t take the bishop but you still preserve an advantage you otherwise have.

“Alekhine’s gun” is less common but it might be worthwhile to add this category