对折的

1.Once it's popped open, your cootie catcher will look like Picture 10.

现在把东南西北这样对折，打开面的小正。

2.The shape of cross-section is an ellipse folded in half through one symmetry axis, and the axis keeps perpendicular with pinacoid-view.

面状为沿对称轴对折的椭圆，此对称轴始终垂直轴截面，其向与平面图的流道中线无关。