Inspired by Macintosh Panther logo, I designed this logo. I started with the letter X of course, then I manually marked the black marks. The second step was to add lighting. I used dodge and burning to do the lighting (while being careful about the nature of light). Then I marked the X layer to Bevel-and-Emboss blending. To give the letter a texture I added a little bit of monochrome gaussian noise. To complete the process I made a copy of the all the layers and inverted vertically then moved the copied layers just below the first X. Then I did a gradient (from white->transparent) to give the glass reflection effect.
You can download the PSD file and see how things were done.