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Abstract Urban agriculture has significant potential to address food security and nutritional challenges in cities. However, water access for urban food production poses a major challenge in the face of climate change and growing global freshwater scarcity, particularly in arid and semi‐arid areas. To support sustainable urban food production, this study focuses on a hybrid urban water system that integrates two important alternative water resources: a decentralized system of rainwater harvesting (RWH) and a centralized reclaimed water system. A new spatial optimization model is developed to identify the best investment strategy for deploying these two alternative water infrastructures to expand urban food production. The model is applied to the case study in Tucson, Arizona, a semi‐arid city in U.S. Southwest, to address food deserts in the region. Results show that 72%–96% of the investment is allocated to rainwater tanks deployment across all investment scenarios, with the proportion of investment in rainwater harvesting increasing as total investment rises. However, rainwater contributes only about 18%–27% of the total food production. The results of our case study indicate that expanding the reclaimed water network is more effective for urban food production and is also more cost‐efficient compared to implementing rainwater tanks. The new model can be applied to other regions, taking into account factors such as crop types, climate, soil conditions, infrastructure configurations, costs, and other site‐specific variables. The study provides valuable insights for planning urban water systems that incorporate alternative water sources under different investment scenarios. 

This paper presents a design for interlocking blocks and an algorithm that allows these blocks to be assembled into desired shapes. During and after assembly, the structure is kinematically interlocked if a small number of blocks are immobilized relative to other blocks. There are two types of blocks: cubes and double-height posts, each with a particular set of male and female joints. Layouts for shapes involving thousands of blocks have been planned automatically, and shapes with several hundred blocks have been built by hand. As a proof of concept, a robot was used to assemble sixteen blocks. The paper also describes a method for assembling blocks in parallel. 

This paper presents a method of computing free motions of a planar assembly of rigid bodies connected by loose joints. Joints are modeled using local distance constraints, which are then linearized with respect to configuration space velocities, yielding a linear programming formulation that allows analysis of systems with thousands of rigid bodies. Potential applications include analysis of collections of modular robots, structural stability perturbation analysis, tolerance analysis for mechanical systems, and formation control of mobile robots. 

This paper presents a method of computing free motions of a planar assembly of rigid bodies connected by loose joints. Joints are modeled using local distance constraints, which are then linearized with respect to configuration space velocities, yielding a linear programming formulation that allows analysis of systems with thousands of rigid bodies. Potential applications include analysis of collections of modular robots, structural stability perturbation analysis, tolerance analysis for mechanical systems, and formation control of mobile robots.