The Origami Forum

You know that center point at the top of a frog base?

Does anyone have any experience closed-sinking that? Is it even possible?*

I'm talking a fully closed and really small sink. Is there perhaps an alternate method for producing such a closed sink?** Something like a series of unsinks and closed sinks?



*(Besides by using a large piece of tear-proof paper--obviously, you could roll it into a cone and shove it through.)

**(Not by blunting the point--that method will almost certainly destroy the paper)

First make a rabbit ear with the flap you want to sink, mountain fold the rabbit ear along the crease line where you want to have the sink, turn the paper over and bring one layer from underneath to the front. If the inner structure doesn´t matter, you can leave it as it is, if not, comes the hardest part ... unfold the rabbit ear inside the model without tearing anything...

This method was described by Lang and should hopefully work.

But that rabbit-eared flap would be wider than the sink, so it wouldn't work. It would work on a hexagonal closed sink though.

It depends on how you make the rabbit ear, you don´t have to use angle bisectors, so you can vary the size of the flap.

I've just done it. What you want to do is to precrease everything and then collapse the paper straight into the closed sink form, instead of making the point and then closed sinking it.

I'll maybe put up photos later.