I was looking up windows pranks, and i thought, why can I do that for a Mac? so i decided to do that. This will show you how to confuse the owner of which Dock to click on!
Step 1: Starting the Prank
First, make sure the dock is not hidden. Then open Grab (if you cant find it, spotlight it) Then take a picture of the screen! (menu bar, capture) and save it somewhere where the owner wont look (but YOU have to remember!!!) then put the dock on the left side. (apple logo in the bar, dock, position on left).
Step 2: Saving the Info Part I
now that thats done, go to the system preferences and then to Desktop & Screensaver. click the little [+] button and FIND the photo you took afew moments ago. it will automatically make the picture the background, and now it appears as if you have 2 docks
Step 3: Add a 3rd Dock (if You Want)
this step is just like the others. take a picture of the 2 docks and save it as the background. then go to the menu bar and move the dock to the right side. now you have three docks!!! If you want it really confusing, make the dock hidden and make it as small as possible