Level 1. LAB, SLAB, BASAL, ALA
Level 2. LIT, GLUT, GILT, GUILT, GUT
Level 3. CAB, SCAB, BIAS, BASIC, SAC
Level 4. TONE, NOTE, ATONE, NEAT
Level 5. SKI, SILL, SILK, KILL, SKILL, ILL
Level 6. BRIE, RIDE, BIRD, BRIDE, BIER
Level 7. LOT, SOOT, TOOL, SLOT, STOOL, LOST
Level 8. DUN, NOB, BUD, BUN, DUB, BOND, BOUND, NOD
