Level 1. FOUR, SOUR, FURIOUS, SURF
Level 2. RIVAL, VIRAL, ARRIVAL, AVAIL
Level 3. SABBATH, ABASH
Level 4. TOUT, TWIT, WHIT, OUTWIT, WITHOUT, WITH
Level 5. GREY, RUSE, SURE, SURGE, SURGERY, URGE
Level 6. DEAL, DIAL, HEAL, HELL, HIDE, IDEA, IDLE, IDEAL, ALLIED, LEAD, DELILAH
Level 7. CALF, CLAY, CULT, FACT, FLAT, FAULT, FACULTY, FLAY
Level 8. PEST, SEEM, SEEP, STEM, STEEP, TEMPT, TEMPEST, TEMP
