challenge
The candidate builds a planner for a 2D robot arm that emits JSON routines the simulator can execute.
Phase 1: hand-author routines for 6 fixed scenes.
Phase 2: ship a JavaScript module that generates routines for scene variants in one family
(capacity, precedence, or obstacle routing).
Evaluation: safety, scene coverage, tradeoffs, and clarity of explanation.
All candidates are expected to complete Phase 1;
senior vs. staff is signaled by Phase 2 — API design, scope selection, and generalization to unseen scenes.