The letters can be done in any way - but on a 7cm square, with them being brought together into a single piece (one per alphabet) at the end.
I chose really simple pencil uncial and watercolour squares, and I'm glad I did, because it's a pleasure never a chore.
I also chose to make the book they're going to live in first - each time I do a letter, I use the colour of the squares to add 2 more squares to the cover of the book.
It looks quite plain in the early photo below - it's looking much more carnival like now! (I was aiming to stay with muted colours, but somehow a few brights have crept in!)
Some of the alphabets are amazing with so much work going in to them - humbling!
Do please have a look HERE