Create a blank image
with 100x100 pixels in size. Draw out a square
with the Rectangular Marquee tool
(Hold Shift button while
dragging)
Set the foreground color
and background color with the darker and lighter
shade of the same color. Now press G on your keyboard and fill
from the upper left down to the bottom right with
the linear gradient tool
.
Deselect the selection
and make a smaller square inside the one you just
made.
Now Rotate it 180
degrees Edit>Transform>Rotate
180.
Create a blank image
with 100x100 pixels in size. Draw out a square
with the Rectangular Marquee tool
(Hold 
Set the foreground color
and background color with the darker and lighter
shade of the same color. Now press 
. 
Deselect the selection
and make a smaller square inside the one you just
made.
Now Rotate it 180
degrees 
Add your text and
shadow.