对折的

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

现在把东南西北这样，打开面小正方形。

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

断面形状为沿称轴椭圆，此称轴始终垂直轴截面，其方向与平面图道中线无关。