On July 28 Gerardo asked about envelopes than open and close by pulling points apart and to share a video if possible.
Chris Palmer has a model like that, he calls it love letter and he keeps one in his back pocket. It opens by pulling opposite corners and then he throws it in the air and it closes by itself (this part I've never been able to replicate completely). I don't think there are videos about this model and unfortunately the model I folded is stored and I don't have access to it right now.
