If you look at the corner of Cherry and Washington St. In San Francisco you will notice a corner that the Zodiac turned to go down to Kahn Playground.
On that corner are three items o let us say 2 items that the Zodiac used to make a mockery of. The S.F. P.D. and the US Post Office with the letters.
You will notice on that corner a US Post Offic box that in the day was painted red, white and blue. You will also notice the call boxes. One for the police and one for the fire dept. Interesting that night he had a bunch of blue meanies, cops, running acound Kahn playground with the fire dept. shining on bright lights. Is this not a mockery he wanted to cause. Look at it from another angle. Every murder has a story. Something to thing about. One last thing there are only two entrances thru that wall that you can walk thru. The one he choose were stairs leading to a dead end and he had to jump down. Irony isn't a bunch of cops jumping down a wall and falling in the dark.