Because touch events are used and I've specified some dimensions, the app is limited to iPad. This may get fixed one day.
The page is trying to use cache/manifest, so should work offline-- but I don't remember if this works.
Go to the url Mixed Letters on the iPad. Save it to your home screen.
Drag the same letters onto each other until there's only one of each left.
Settings allows you to choose which letters to use, and how many of them. You can also chose the font to use, and whether lower case letters are considered the same as the upper case letters.
Settings are saved for the next time.
I was intending to be able to mix different fonts in the same game; but this is causing some display issues because font metrics are different.
Simple customisation would be to edit the html file to change the available fonts, and perhaps add some choices of "sets" of letters for easy selection. Host the page yourself. If you don't have a web host, use your public Dropbox folder. (Don't have Dropbox? Why not? Here's a Dropbox referral link -- using it will get us both a little more space.)
Let me know what you think.