Paper used in this video: square with a side length of 15 cm (6 in), kami; half a square: 7.5 cm by 15 cm (3 in by 6 in), kami
Finished model: 12 cm (4 3/4 in) long, 5 cm (2 in) wide
This video describes how to fold a fantastic origami action model: a singing frog designed by Daniel Chang (aka mitanei).
When you release and pull the lever, the frog opens and closes its mouth. The heart-shaped eyes suggest it might be singing a love song. :)
Daniel Chang kindly gave me permission to make this video accessible to you.