Auxetic materials exhibit a negative Poisson's ratio when subjected to mechanical load. [1][2][3][4][5] For example, auxetic structures expand longitudinally and laterally when subjected to uniaxial tension instead of experiencing lateral contraction commonly seen in their conventional counterparts. Researchers have broadly considered the use of such materials and structures in many applications, including but not limited to biomechanics, flexible electronics, and soft robotics. [6][7][8][9] The growing interest in using auxetic structures in these applications is due to their improved mechanical properties, such as higher indentation resistance, improved vibration damping, resistance to shear, and enhanced fracture toughness, compared with their nonauxetic counterparts. [10][11][12][13] Auxetic structures are generally classified as a subset of "mechanical metamaterials" as their novel properties are not commonly found in nature or other conventional engineering materials. [3,14,15] The so-called mechanical metamaterials are highly influenced by the augmentation of their local morphology. Therefore, their physical properties can be controlled by certain microstructural and geometric features, thus allowing broader control of the behavior by design rather than the chemical composition of their constituent materials. [16,17] Property-adjustable auxetic materials with variable responses in changing environments have also been developed for various applications. [18][19][20][21][22][23] For instance, embedding magnetic insertions in auxetic metamaterials is shown to change the cellular configuration upon the application of a magnetic field, switching nonauxetic to an auxetic response. [24] Similar behaviors have been observed when a quadrilateral cellular structure consisting of bimaterial strips converts into a convex or concave shape with thermal triggers. [25] Researchers have explored various cell topologies that lead to auxetic behavior. [3,5,[26][27][28][29] The pioneering experimental studies in this field are credited to Lakes, who investigated auxetic foams. [30] In recent years and in line with the advancements in additive manufacturing, practical and cost-effective pathways to the realization of these architected structures have become more easily achievable. [31][32][33][34][35][36][37] Specifically, the fabrication of planar mechanical metamaterials with tunable properties has attracted great attention. For example, the cut and slit design strategy, wherein perforations are intentionally introduced into a sheet to promote auxeticity, has been explored in several studies. [35,38,39] These perforation patterns used to achieve auxetic behaviors include kagome lattices, [39] diamonds, [40] circles, [41] triangles, [42] ellipses, [43] stars, [31] self-similar squares, [44] and rectangles. [17,35,36] The auxetic response has also been achieved through randomly
