Letter on position 1 (w) changed: 12 words bast cast east fast gast hast last mast oast past rast vast Letter on position 2 (a) changed: 3 words west wist wost Letter on position 3 (s) changed: 6 words wadt waft wait want wart watt Letter on position 4 (t) changed: 4 words wase wash wasm wasp