Car loads C passengers, runs when full, then unloads. Multi-car extension requires ordered loading/unloading using semaphore lists. Last passenger signals completion with allAboard and allAshore rendezvous ensuring synchronization phases.
Four-person boat with composition constraints preventing unsafe combinations (1 hacker with 3 serfs or vice versa). Captain selection, scoreboard pattern, and barrier synchronization ensure all board before rowing with proper crew composition.
Assembles water molecules from oxygen and hydrogen threads requiring 2H + 1O combinations. Uses barriers for complete molecule formation before proceeding. Demonstrates ambiguous mutex exit points and non-traditional lock release patterns.
Santa coordinates with 9 reindeer and multiple elves. Wakes for either all reindeer or 3 elves, prioritizing reindeer. Uses counters, mutual exclusion, and elfTex turnstile preventing new elves during service with batch processing.
Complex barbershop with 3 barbers, 4 sofa seats, 20 capacity, and single cash register. Uses dual queues, multiplexing, and payment synchronization. Demonstrates advanced concurrent resource management with capacity constraints and FIFO ordering.