—One of the grand challenges of self-reconfiguring modular robotics is the assembly of a functional system from thousands of components. However, to date, only systems comprised of small numbers of modules have been demonstrated. One approach to scaling to large numbers of modules is to simplify module design by relieving the modules of the typical power, control, and actuation requirements necessary for locomotion. Assembly is accomplished by taking advantage of stochastic environmental motions to move the modules into place. Here we present an experimental system in which we assemble 3D target structures stochastically from simple, 15 mm-scaled components by manipulating the fluid