update 2: Turned out update 1 didn't work out so much as I thought, I am still trying to figure out how to make it better. In the meantime, I tried this one. It was supposed to be Y and Z overlaid, and recognizable enough. But I am not sure how to fill the color to serve that purpose. What I did in this one was simply put Y in yellow (multiply) on top of Z in blue. :p
update 1: I tried it out in Illustrator.
Y and Z are my initials so I started to play with them. I wanted to put them on top of each other and make them recognizable with different fill or stroke colors in the end; but first I need to make sure each of them is right as an individual.
Then I decided to make both of them uppercase, so they'll be of the same height. That's all for now. :p