The simplest rigidly foldable single-vertex origami structure is a four-crease origami (single 4C). It is a 1 DOF spherical linkage which possesses geometric properties that allow its copies to be combined into more complex rigidly foldable origami such as the Miura-ori. Merging two identical flat-foldable single 4Cs together produces a new construction, called the double 4C. We discover that this composite structure has some unique kinematic properties. Apart from being rigidly foldable and flat-foldable with 1 DOF, both single 4Cs in the double 4C are always in identical folded states. Moreover, it actually couples some panels together to form scissor-like mechanisms without physically crossing the panels. The double 4C can also have its kinematically equivalent thick-panel counterpart. By dissecting the double 4C and its thick panel counterpart, we find the constituent mechanisms forming them. We uncover how the constituent mechanisms evolve. Since the double 4C are fundamental units in many stackable tessellation origami structures, our kinematic analysis gives insight into the kinematic behaviour of these structures. Not only the findings can also be used to guide the creation of thick panel counterparts of the stackable origami, but it may also enable the creation of new origami structures with single DOF by mimicking the vast number of deployable structures that contain scissor-like elements.

最简单的刚性可折叠单顶点折纸结构是四折痕折纸（单4C）。它是一种 1 DOF 球形连杆机构，具有几何特性，使其副本可以组合成更复杂的刚性可折叠折纸，例如 Miura-ori。将两个相同的可平折叠单 4C 合并在一起产生一种新结构，称为双 4C。我们发现这种复合结构具有一些独特的运动学特性。除了可刚性折叠和 1 DOF 平折外，双 4C 中的两个单 4C 始终处于相同的折叠状态。此外，它实际上将一些面板连接在一起，形成剪刀状机构，而无需物理交叉面板。双 4C 还可以拥有其运动学等效的厚面板对应物。通过剖析双 4C 及其对应的厚面板，我们找到了形成它们的组成机制。我们揭示了组成机制是如何演变的。由于双 4C 是许多可堆叠棋盘格折纸结构中的基本单元，因此我们的运动学分析可以深入了解这些结构的运动学行为。这些发现不仅可以用来指导可堆叠折纸的厚面板对应物的创建，而且还可以通过模仿大量包含剪刀状元素的可展开结构来创建具有单自由度的新折纸结构。