The Origami Forum

Hi! I know the topic of Hideo Komatsu's has been brought up many times and I've looked at as many threads as I could, but I still can't figure out how to complete it. I think I collapsed it properly, but I can't be sure. Can someone please post an image of the backside of the model? I think I can figure it out with that...

Edit: I've figured more of it out but I don't know how to sink the back...

Brute force... at least the first time, then you can unfold it and try to add a suitable pre-fold.

can someone help me steps 19-21?

Am also stuck in step 19-21, any help will be greatly appreciated!