Letterbox for the Nintendo 3DS was popular, but was suddenly removed under mysterious circumstances some time ago.  Fans have been wanting something to replace it, and now Nintendo has delivered Swapdoodle.

Much like Letterbox, Swapdoodle allows you to send drawings to your friends using the Nintendo 3DS stylus and you can share drawings with people on your Friends List using SpotPass.

The application is free to download, but optional Lessons can be purchased that teach you how to draw Nintendo characters.  Lessons cover popular franchises such as Animal Cross, The Legend of Zelda and Splatoon.  A Lesson Pack will unlock 12 of these Lessons.

The purchase of the Premium Pack, which includes these lessons, also allow you to use more ink and colours in your messages.  A Sparkling Premium Pack is also available to purchase from within the app.  You can also trial lessons available in these packs, but only once, and while you cannot save or send your results you can trial the lesson in its entirety.

You will also be able to add some software icons to your messages as a way of showing off what you have played.

It is available on the eShop now.