Each of the following sentences contains clues to a set of three words that are spelled the same, except for one letter (each sentence describes a different set). Example: malt, melt, molt.
1) Billy discovered a cylindrical chest buried beneath the knoll.
2) The only evidence found by the detective was some adhesive in the chimney passage.
3) The bashful bovine rested on the small bed.
4) The latest fad was for people to desire the ingestion of a tall wading bird.