Ready? Start by thinking of a 2-digit number. Any number from 01 to 99. Don’t tell me what it is.
Now get out your calculator and multiply the number by 101. Then add 12. Then subtract the number that you started with. Now square the result (multiply it by itself). Then subtract 8. You should now have a large number somewhere between 5 digits long and 8 digits long. Don’t tell me what it is.
Keep the last 4 digits only. Throw out the rest. You now have a four digit number in the form ABCD. Change the B to a 1. (For example, if you ended up with 7654321, then keep only the last 4 digits 4321and change this to 4121). Again, don’t tell me what it is because I can read your mind to find it. Concentrate hard on it. And I think I have it. Now wait until I place the cache in the location that you are thinking of.
(pause)
OK. It’s ready for you.
Go to the posted coords. You will see sidewalks going off in all directions. You want the sidewalk on the east side of the road, going south (not precisely south but close enough). Starting on the sidewalk close to the posted coords, walk south for "BCD" meters. (For example, if your number was 4121, you would walk for 121 meters).
Now turn left and walk east for "CD" meters. (Use waypoints to get a precise distance). Then turn right and walk south again for another "CD" meters.
Now measure “A + D” inches above your head and TA-DA, there’s the cache. Right where you told me to put it.