Temperature controls the roast you get. just a few degrees means a world of difference as this attractive chart show.
Circular Glyphs by Irolan.deviantart.com on @DeviantArt
Image from http://fc06.deviantart.net/fs71/i/2010/176/a/1/Angelic_Alphabet_by_Raiyze.jpg.
Alchemy Table of symbols - Imgur
Dragon Language by Tarrenger
Throne Codex by ProjectWarSword on deviantART