This is my newest app created for both Windows Phone and Windows. Supported version is 8.1 or above.
Current time is shown, and the background color changes based on the hexadecimal representation of the time. The app is created for fun, and it is an experiment in the world of Universal Windows Apps.
Colors can be represented in the following format: #RRGGBB, where RR is the amount of Red, GG is Green and BB is Blue. The mix of these values gives one color. Each characters can range from 0 to F, which makes up the hexadecimal system. 0 to 9, A, B, C, D, E and F values in six places produces 16,777,216 different number of colors. Higher values mean lighter color, so #000000 means full black, and #FFFFFF means white.
Of course in our case the time will go maximum of #235959 so we will see most often darker and greenish-bluish colors as the minutes and seconds go higher volumes.
I hope you will find useful this little explanation and try out What Color is it.
Windows Phone 8.1
Here are some screenshots for you to get the idea: