The Up-Goer Five Text Editor in Thai language. Pun means thousand and Come means word. The name is 1,000-intended.

It's the xkcd comic that the author tries to explain hard things like Saturn V rocket using only the common 1000 words. You can try the English version.

Try to write and/or explain something using easy Thai words. They'll be highlighted in red if they're not within 1,000 common Thai words. Implementation should be harder than English because writing in Thai does not have spaces between words.