You can paste the letter on the drawing canvas and use the mouse to draw on the canvas.
Maybe this Scirra example project can do something for you.
editor.construct.net
Or, on my youtube channel are a lot of beginner friendly tuts where you can learn how to make some well known games by example.
youtube.com/channel/UCZ6QjvqEs9dR2miRnfFqIpQ
There's also a little demo where you can see how to use the paste functionality of the drawing canvas :
youtu.be/5kZD3SAuHwc
Hope I helped you
Cheers