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Abstract Liquid metals (LMs), renowned for their high conductivity and large deformability, find increasing applications including in flexible electronics and soft robotics. One critical process in these applications is the precise patterning of LMs into desired shapes. Yet, existing LM patterning techniques predominantly focus on 2D patterns due to challenges posed by the inherent fluidity and leakage of LMs. Here, we introduce an approach that bypasses these limitations, enabling the creation of complex 3D leakage‐free LM structures. This is achieved through mechanical programming of 2D magnetically immobilized LM paste formed via incorporating magnetic particles into LMs. Such composite effectively resists leakage due to the combined effect of strong magnetic inter‐attraction within the porous magnetic networks and the high surface tension of LMs, while retaining the high conductivity. Diverse freestanding magnetic LM structures, obtained upon LM solidification at ambient temperature, dynamically morph between their 2D and various 3D configurations through multiple cycles of induction heating and magnetic‐assisted reprogramming, featuring large compression resistance and self‐healing capabilities. Potential applications of these leakage‐resistant, shape‐adaptable structures are demonstrated through a helical magnetic LM antenna, which showcases its efficiency in wireless communication and energy harvesting. 

Abstract Fourier ptychography (FP) is an enabling imaging technique that produces high‐resolution complex‐valued images with extended field coverages. However, when FP images a phase object with any specific spatial frequency, the captured images contain only constant values, rendering the recovery of the corresponding linear phase ramp impossible. This challenge is not unique to FP but also affects other common microscopy techniques — a rather counterintuitive outcome given their widespread use in phase imaging. The underlying issue originates from the non‐uniform phase transfer characteristic inherent in microscope systems, which impedes the conversion of object wavefields into discernible intensity variations. To address this challenge, spatially‐coded Fourier ptychography (scFP) is presented for true quantitative phase imaging. In scFP, a flexible and detachable coded thin film is attached atop the image sensor in a regular FP setup. The spatial modulation of this thin film ensures a uniform phase response across the entire synthetic bandwidth. It improves reconstruction quality, corrects refractive index underestimation issues prevalent in conventional FP, and adds a new dimension of measurement diversity in spatial domain. The development of scFP is expected to catalyze new research directions and applications for phase imaging, emphasizing the need for true quantitative accuracy with uniform frequency response.