Three-legged

What is it that having one voice becomes four-legged and two-legged and three-legged?

Tom and Mary competed together in the three-legged race on sports day.

You need at least four people for a three-legged race.

"We came here on business," said Stamford, sitting down on a high three-legged stool, and pushing another one in my direction with his foot.

The three-leggeds had everyone in stitches. Some pairs simply could not learn to run together — just impossible.

My father said that three-leggeds are more detestable than four-leggeds.

With respect to hazard rating, an opposite and possibly inconsistent explanation might be offered: It may be that drivers underestimate roadside hazards at three-leggeds and relatively speaking overestimate them at four-leggeds.