The cube teapot is a teapot

Teapot

A teapot is a vessel used for steeping tea leaves or a herbal mix in near-boiling water. Tea may be either in a tea bag or loose, in which case a tea strainer will be needed, either to hold the leaves as they steep or to catch the leaves inside the teapot when the tea is poured...

 whose main purpose was to be used on a ship whereas normal teapots would roll over when the ship rocked from side to side. The cube shape of the teapot would stabilise it and it wouldn't roll over and scald the person making the drink.

The teapot was invented by Robert Crawford Johnson

Robert Crawford Johnson

Robert Crawford Johnson was the English inventor of the cube teapot....

, who was responsible for the design and registered "Cube Teapots Ltd" in 1917. He perfected the design, one that did not drip, poured easily, was chip resistant and stacked together for easy storage. With no spout or projecting handle the cube teapot looked exactly as it sounds - a cube.

Although the teapot was registered in 1917, the teapots were actually first put into production in 1920.

The teapot was used by Cunard

Cunard Line

Cunard Line is a British-American owned shipping company based at Carnival House in Southampton, England and operated by Carnival UK. It has been a leading operator of passenger ships on the North Atlantic for over a century...

 on the Queen Mary liner

RMS Queen Mary

RMS Queen Mary is a retired ocean liner that sailed primarily in the North Atlantic Ocean from 1936 to 1967 for the Cunard Line...

.