Yahoo Inc has begun publicly testing two Web services that are the fruit of intensive, one-day internal programming competitions the company has been hosting to foster employee innovation.

One of them, MapMixer, will let users take the millions of maps on the Web and overlay them onto the same locations on Yahoo Maps -- creating hybrid maps that work independently of the underlying format or structure of the different maps.

While certain spots can be denoted on maps from Yahoo and rivals Google Inc, Microsoft Corp, and AOL, MapMixer gives non-technical users a way to merge a map of a college campus or a group of local landmarks or a historical map of a town with a Yahoo road or satellite map.

MapMixer was a winner in a product design competition held at Yahoo's Sunnyvale, California headquarters in March.

I get most of my best ideas either while I am showering or just before I go to sleep, said MapMixer's creator, Nimit Maru, an engineer who normally works in Yahoo's travel business. This is one of those showering ideas.

Hack Days are 24-hour day-and-night competitions that seek to break down barriers between product groups within the organization in order to build rapid prototypes of workable Web services that the company can in turn commercialize.

The events have been held quarterly since late 2005 at Yahoo offices around the world, from its Silicon Valley headquarters to London, New York and Bangalore, the Yahoo manager in charge of spearheading the exercises said.

'Hack Days' are about expressions of creativity, Bradley Horowitz, vice president of Yahoo's Advanced Development Division, said in a phone interview. I want people to do really wild, speculative stuff.

MapMixer is now being publicly tested and can be found on a link off Yahoo Maps or at Once on the MapMixer page, users can upload a map in a variety of image formats, including popular types such as .jpeg or .gif.

Once a map is uploaded, a user can meld it with any Yahoo map. After locating it on the Yahoo Map grid, MapMixer places the uploaded map and rotates and scales it, calculating how to make the maps work together on different computers, Maru said.

The program then snaps the two together to create a hybrid map that can be saved for personal use in a My Maps account.

It started out with the idea first, said Maru, 24, a graduate of the University of Illinois, Champaign-Urbana. The technology came later. To turn MapMixer into a product, the engineer was given time off from his normal duties in Yahoo Travel to collaborate with employees in the Yahoo Maps team.

A second application Yahoo is introducing is Shop by Color, a feature to make it easier to search by color for products on its shopping site. It was created by Yahoo Shopping employees Hayro Kolukisaoglu and Sundeep Tirumalareddy.

Online shoppers will be able to filter their search for items such as shoes or pants by selecting from 56 color hues.

Selecting specific hues will filter searches to locate any similar results, regardless of the color name used by a product maker, be it tangerine or orange, charcoal or slate gray.

Other hacks that have evolved into products include Yahoo Messenger Flight Planner, a plug-in software program that allows users to use the company's instant communications program to simultaneously plan trips, officials said.