1125 Stockbroker Grapevine (1)
1847 Tram (1)
3259 Wormholes (3)
3169 Layout (4)
2253 Frogger (4)
3255 Roadblocks (5)
1556 The Doors (5)
2502 Subway (6)
1344 Tree Size Problem (6)
3463 Sightseeing (6)
2135 Farm Tour (7)
2404 Jogging Trails (9, challenge problem)