Thank you for the detailed review! It's certainly true what you said about how people's interpretations are all different when it comes to how a letter is drawn or should be made. For this reason we tried to include as many recipes as we could think of for every letter, so that every letter has more than one recipe. That way we could attempt to account for what people may think of in advance. Of course player's are always going to be more creative than us with their ideas so there's always more recipes we could add after the jam.
The biggest issue (and fun design challenge) with coming up with the letter recipes is that sometimes you have letters which could have the exact same recipe. Probably the best example of this is L and T. Both letters where the assumption that it should be a I and a rotated I is totally fair. We decided to give that recipe to L because we could use L to make T, but couldn't do that in reverse. Situations like that explain why sometimes you can find examples of recipes like the one you showed for X and Z. Once we are able to add support for reflection + rotation combined, we will have more options to disambiguate (such as another recipe for T involving two L's...), but we really wanted to get as many recipes as we could possibly think of in the time allotted.
Last I wanted to comment on your idea about a way to remember recipes. I am SO excited about the idea of having a recipe book in the game, that fills out as you discover all the recipes we have for all the letters. I hope that when/if we have this feature in the game that it will make that experience more enjoyable for players.
Thank you for all your kind words, feedback, and again for the detailed review!