Fig. 1: Illustration of the real-time in situ magnetization reprogramming method.

a, Under a uniform magnetic field, several demonstrations of deformation are achieved through the proposed reprogramming method, ranging from (i) 1D tubes to (ii) 2D sheets and progressing to (iii) 3D box-shaped structures, with transformations occurring at different moments (Supplementary Videos 1 and 2). All objects are suspended, with (i)–(iii) shown in the front view and (iv) in the bottom view. In (i), the tube transitions from a straight line into a helix without changing the magnetic field. The colour of the tube in (i) was digitally adjusted from black to red for enhanced visualization, whereas the objects in (ii)–(iv), originally red, were left unmodified. b, The 1D magnetization reprogramming. (i) Multiple tubes, each embedded with a magnetic unit, undergo a nested assembly to form an integrated tube. R_i represents magnetic unit i, in which the blue arrow indicates the magnetization direction of the magnetic unit. d_Rii+1 indicates the distance between the magnetic units i and i + 1. (ii) The reconfiguration is achieved through the relative movement between tubes, resulting in different magnetization profiles. (iii) Magnetization expansion of a single tube. In (i), each tube contains one magnetic unit, which can be expanded to n magnetic units with varying magnetization directions. NT, number of tubes; NM, number of magnetic units. (iv)–(vi) Shape change of configuration B. Data in (v) are presented as mean ± s.d. (n = 3 tests). In (vi), when d_R12 = 0 mm, the tube undergoes negligible deformation as the magnetic field increases from 0 mT to 100 mT. c, The 2D magnetization reprogramming. Left, the number and positions of the magnetic units within the sheet can be arbitrarily configured and altered. Right, shape changes of sheets with two different magnetic unit positions (Supplementary Video 2). Scale bars, 5 mm.