Level 1. DUG, JUDGE, DUE
Level 2. ROT, HOT, FOR, FORT, FORTH
Level 3. OLD, FOOL, FOLD, FLOOD, FOOD
Level 4. EAR, ARE, SEAR, EASE, ERASE
Level 5. BORN, ROBIN, IRON
Level 6. TON, ROT, HORN, THORN, NORTH, HOT
Level 7. WEAK, WAKE, AWAKE, AWE
Level 8. SON, LOAN, SALON, ALSO
