Above right: two enlarged ‘hidden’ Tetragrammatons. Apologies for the quality of the pictures - I only had a small digital pencam with me.
The most interesting section by far is the column of the ten sons of Haman. Aside from the well known tradition of having to recite all those difficult names in one breath in order to avoid seeming that is gloating over the enemies downfall, there is a very specific way of writing this that involves placing the names of the sons on the far right of the amud and the word v’et (and) on the far left. In a brick on top of brick structure. This is because unlike the brick overlapping brick structure of the song of the sea, this structure would easily topple signifying how evil will easily topple if pushed. They must be written in one column which is why they generally all have to be enlarged unless it is an eleven line megillah. The word ish (man) must start the column and the word aseret (ten) must end it.
Three of the sons have small letters in their names, the tav in Parshandata, the shin (and tav?) in Parmashta and the zayin in Vayzata, however as with the chet in chur (diary 14), I can find no explanation for this.
In contrast some say the shin in Parshandata is large (though in all megillot I have seen it never has been). The most gruesome tale regarding letters I have come across is that of the giant vav at the start of Vayzata (the tenth son at the very foot of the column). This has to be much larger than any vav in Scripture. Indeed, according to R. Zeira in Masechet Sofrim, it must project like a boat-pole on the river Libruth (wherever that is!) Why? Because all the sons were strung up from one pole! This charming little visual midrash is courstesy of R. Yochanan in Megillah 16b - wouldn’t like to have met him on a dark night - strange boy.