Soap B.J. Johnson Soap Company, introduced "Palmolive" brand soap that same year. This new brand of soap became popular rapidly, and to such a degree that B.J. Johnson Soap Company changed its name to Palmolive. In the early 1900s, other companies began to develop their own liquid soaps. Such products as Pine-Sol and Tide appeared on the market, making the process of cleaning things other than skin, such as clothing, floors, and bathrooms, much easier. Liquid soap also works better for more traditional or non-machine washing methods, such as using a washboard. A variety of methods are available for hobbyists to
Kirkman's schoolgirl problem process within the problem of organising a large group into smaller groups where no two people share the same group twice can be referred to as orthogonal regrouping. However, this term is currently not commonly used and evidence suggests that there is no common name for the process. The Oberwolfach problem, of decomposing a complete graph into edge-disjoint copies of a given 2-regular graph, also generalizes Kirkman's schoolgirl problem. Kirkman's problem is the special case of the Oberwolfach problem in which the 2-regular graph consists of five disjoint triangles. Kirkman's schoolgirl problem Kirkman's schoolgirl problem is a problem in combinatorics