Location: Fort Baker
I'd visted Fort Baker a couple of years earlier. The main thing that stood out in my memory from that was watching Santa Claus run along the road, chased by some guy, Santarchy in October.
This time, there was no Santa Claus. Instead, we spotted jolly burninator Doug Zongker sitting behind a sign. He didn't seem to be handing out puzzles from a sack. Where, exactly, was our next puzzle? In solving the previous puzzle, we had rendered a picture, a picture of a vista. If we could find the place from which we could see this vista, we could find our next puzzle. That seemed hard--the picture was pretty low resolution. Instead, we asked a small boy where all the other funny-looking people had run to. He pointed us at a big plastic box amongst some rocks down by the shore. Greg quickly clambered down and fetched our next puzzle: a bag full of strangely-shaped wooden blocks.
These blocks were covered with letters. Well, not totally covered with letters. There were some blank surfaces. And there were some transparent blocks. The letters were different colors. This puzzle was actually three puzzles.
Looking at the red letters on blocks, it seemed clear that we were trying to assemble a message. One block had the word "blue", and it was pretty easy to put together blocks to form the word "square" with red letters. Soon we had the blocks laid out in a rectangle, red letters facing up, spelling out a message. The message started "blue:", and challenged us to build a certain shape.
We re-assembled the blocks into the proper shape, this time with blue letters facing out. They spelled a message, a message telling us to build something else, this time paying attention to the green letters. That sent us on our way to the Richardson Bay Audubon Center, otherwise known as "that one cute house on the way out to Tiburon".