Letter on position 1 (b) changed: 7 words curl furl gurl hurl murl nurl purl Letter on position 2 (u) changed: 2 words birl byrl Letter on position 3 (r) changed: 2 words buhl bull Letter on position 4 (l) changed: 10 words bura burb burd burg burk burn burp burr burs bury