Self-replicating hierarchical modular robotic swarms | Communications Engineering

paper Abdel-Rahman, Cameron, Jenett, Smith & Gershenfeld Apr 6, 2026

MIT CBA paper demonstrating a discrete modular material-robot system capable of serial, recursive (self-replicating), and hierarchical (building larger robots) assembly. Small robots build copies of themselves and larger robots from the same modular building blocks used for the target structure. Combined recursive + hierarchical assembly achieves throughput scaling of O(2^N), matching biological self-assembly (ribosomes). Challenges the convention that large constructions require large machines.

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Large constructions do not require large machines. Small robots can build copies of themselves and larger robots, which in turn build even larger ones — matching the exponential throughput scaling found in biological assembly. — Abdel-Rahman et al., MIT CBA →

Discrete Modular Materials Discrete modular materials are structures composed of a finite set of simple, identical building blocks that connect reversibly. Global precision emerges from local geometry — each block snaps to its neighbors with fixed alignment, so errors don't accumulate (Abdel-Rahman et al.). →

Exponential Assembly Scaling Serial assembly throughput decreases as structure size grows — more time is spent traveling, not building. Self-replication and hierarchical assembly together reverse this: throughput increases exponentially with scale (Abdel-Rahman et al.). →

Hierarchical Assembly Biology does this naturally: ribosomes assemble amino acids into proteins, proteins into organelles, organelles into cells, cells into organs. At each level, the "assembler" is built from the output of the previous level. The result is exponential throughput scaling across orders of magnitude (Abdel-Rahman et al.). →

Hierarchical Assembly Hierarchical assembly builds structures through multiple scales: small assemblers compose small blocks into larger blocks, which become the building material for larger assemblers, and so on. Each level up reduces travel distance per unit of material moved. →

Material-Robot System A material-robot system erases the boundary between the robot and the material it builds with. The robot is a temporary configuration of the same discrete modular blocks that form the target structure (Abdel-Rahman et al.). →

Continuous Assembly

Desired State Systems — the pattern: declarative over imperative with reconciliation (bib)
NixOS — declarative OS as canonical desired-state system (bib)
GitOps for Fleet Management — desired state applied to device fleets (bib)
Self-Replicating Robotic Swarms — recursive + hierarchical physical assembly (bib)

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Self-Replicating Hierarchical Modular Robotic Swarms Abdel-Rahman et al. (MIT CBA, 2022) demonstrate a discrete modular material-robot system capable of serial, recursive, and hierarchical assembly (bib). →