Snail colony -- more questions than answers

I took this pic while backpacking the west coast trail.   We tried to walk the beach, whenever the tides permitted.  One day, we discovered this colony of sea snails huddled together clinging to a rock that would soon be covered by the rising tide.  The snails are so small a penny would cover a few of them.  
What I wonder is why are they so closely packed together?  Are they drawn to each other?  Are they each vying for a prime patch of real estate that has the perfect combination of food and foothold?  Are they procreating?  Are they just huddling together for protection, with those on the outside most vulnerable?  How long do they stay clustered together like this?

You want me to do what?

I'm a big fan of public transit, especially the rapid transit variety, like Vancouver's skytrain. Last year, partly in preparation for the 2010 Olympics, we were blessed with a brand new line from downtown to the airport and to Richmond, where I live. It's called skytrain because the train runs on a track that's elevated above ground. I brought my bike along one day and bikes aren't allowed on the escalators or stairs, so you must take the elevator. Seemed simple enough, until I got inside and was greeted with a set of buttons I just could not figure out!

I thought that these might be imported elevators that still have the buttons in the local language, so maybe C means up and S means down??

Ended up pushing both C and S, ignoring the 4 buttons, each with double arrows that seemed to be twice too many ways of opening and closing the doors.

Doors close. Rumble, rumble. Doors open, but instead of seeing a platform of people, I just see another elevator across from me. So, I go across and enter, expecting to see another S and C. But no, now I have 3 buttons: C, CR and T !! (still ignoring the 4 buttons that seem to open/close the door)

Yowzahs! So, I push all 3 and up it goes.

When I got off at my destination, I unlocked the mystery of the buttons, thanks to a kind soul who handwrote the meaning of the buttons:
S = Street level
C = Concourse level
CR = Concourse level, Rear door
T = Train level

No indication of why there are 2 sets of door open/door close buttons.

Sigh.

Needles taking shape after the rain

Nothing like a good rainstorm to clear the air and wash clean the street.  Here are some pics of our street after a rainstorm that was heavy enough to cause little rivers to form.  All that remained of the rivers afterwards were fir needles heaped up to create interesting shapes and patterns.

Nice swoosh shape

Looks like the little river flowed around these weeds

Needles in beautiful alignment

Fantastic pattern of needles in neat horizontal lines on a background of randomly oriented needles

Large dense swirl surrounded by randomness