Pop-up Paper

Fold one corner like in the picture. This is the trickiest part of the project. I managed to do this by just starting with one of the ridges. Fold from the edge of the paper to the diagonal X-ridge. Then make the other perpendicular fold the same way. Finish that corner by folding the outer part of the X-fold the other way. Notice that the X-fold made earlier has to be folded upwards in the corner

[mono_mania]

紙を広げやすい形に折りたたむ方法