Letter on position 1 (b) changed: 12 words cast east fast gast hast last mast oast past rast vast wast Letter on position 2 (a) changed: 3 words best bist bust Letter on position 3 (s) changed: 6 words baft baht bait bant batt bayt Letter on position 4 (t) changed: 4 words base bash bask bass