I've been in a very "modular origami" mood lately. The pieces for these two models are very easy to make but the assembly is a nightmare, I think I had less trouble with the 5 intersection tetrahedra. I found the left model unit here and learned the right model here: link
The units for the model on the left can be described in four steps:
Divide into quarters(like an accordion)
Fold the corners in
make a line connection the corners
The trouble comes with having too many points that have to go into one flap on one side which makes it very uncomfortable to insert the last few pieces. This unit is heaven in comparison to the assembly of the model on the right, might have been just cause I took a paper that was too small(1/2 A4 for whole model, 30 units).
Here's the steps for the right one, units are made of 1:2 rectangles
Turn
This step is hard to understand at first but isn't that bad when you figure it out, you have to balance out the corners touching the edges and the edges in the middle lining up(parallel).
Fold in half
unfold and thin the flap from the corner on both sides as shown
This is the complete unit
Got a cute picture of the cat today in the morning :D
Also while riding my bike I happened to notice a nest over a door, then I noticed these little guys. Couldn't catch the mom swallow since she was going back and forth feeding the birdies. really made my day.
Thanks for reading, just a reminder not to try the models if you value your nerves :p