Level 1. RUG, PURE, URGE, PURGE
Level 2. FRY, FIRE, RIFE, FIERY
Level 3. RAVE, VANE, NEAR, RAVEN, EARN
Level 4. DEN, NEED, KNEE, KEEN, END
Level 5. FAR, AIR, FAIR, FAIL, FRAIL, RAIL
Level 6. ROB, BAD, BAR, BROAD, BOARD, ROD
Level 7. EVE, EVEN, NEVER, NERVE, EVER
Level 8. SET, TEA, SEA, EAT, LET, STEAL, LEAST, EAST
