Level 1. SIT, TAR, RAT, STIR, STAR, STAIR, SIR
Level 2. SEW, WET, SEE, WEST, STEW, SWEET, SET
Level 3. SLAP, LAMP, PALM, PSALM, SLAM
Level 4. NAG, RAG, ARE, RANGE, ANGER, AGE
Level 5. FARM, FAME, FARE, FRAME, FEAR
Level 6. VILE, VEIL, EVIL, LIVE, VALE, VEAL, ALIVE, VIAL
Level 7. PEN, NEED, EXPEND, END
Level 8. GRIN, RING, IRON, ORIGIN
