This document discusses dynamic round-trip engineering in the context of feature-oriented model-driven development (FOMDD). FOMDD allows modeling software at different levels of abstraction with features. The document proposes a solution using Pharo classes as executable containers for models and a mediator object to ensure consistency during dynamic round-trip engineering. This would let developers investigate solutions from any place without stopping or restarting, enabling multi-platform software prototyping and assessment.