Fluid layouts are often compared to water, but water isn’t always fluid. H2O has three different states, and depending on the temperature can be a solid, liquid, or gas, transitioning seamlessly from one to another at specific points (0ºC, 100ºC). An infinite grid also has multiple states (single column, multi-column, etc.), and should transition as seamlessly as possible between them at specific breakpoints as well. For example, just as ice is an appropriate state for water when the temperature is low, a single-column layout may be the appropriate state for an infinite grid on smaller devices.
Water’s state change is caused by the rearrangement of its molecules. When an infinite grid changes state, we rearrange its components.