Select the round rectangle tool, turn on paths and set the radius to 10 px. Create the tower in path selection then go to Edit > Transform path > Prespective. Edit the bottom paths to make it winder.
Fill path #AAAAAA.
Step two:
Add the following layer-styles:
Blend Mode: Normal
Opacity: 100
Gradient: Default
Reverse: Check
Style: Reflected
Aligh with Layer: Check
Angle: 0
Scale: 150