Marty says

I used ryans letters, but I like the idea to continue the color spectrum of the OCAL logo more. Therefore I changed this to the colors that I used in my previous entry.

Further more I used a simple copy of the white outlines for the shadows. Ryan increased the size of the duplicated objects. For the monochromatic version the shadow is a little bit closer to the object to accentuate the letters a little bit more.

In general I prefer to use the letters itself as overlapping objects and not letters which are displayed on a square, how ryan suggest it in the second part of his entry. The overlapping letters are an easy to understand contrast to the OCAL logo. Simple cards represent clip arts - overlapping letters represent fonts.