Symbols on the Ground and Elsewhere in Washinton DC?

Question

Hi, I need a native or longtime Washington DC'er to help me out. My family and I recently visited the great area of Washington DC and we noticed two symbols that we seemed to see throughout the area: One was a white "robot" or "martian" symbol painted on the ground at several crosswalks in the intersections, even one that was made out of colored sticks that were glued on the back of a street sign, (I have a picture of that one) the other symbol we noticed several times here and there were stickers of "snails" pleaced throughout the city. We meant to ask someone before we left what they signified, but forgot to. Now we are back, yet still dying to know. If there are any local DC residents that could help put us out of our curious misery, we would be greatly appreciative! Thanks!

Answer 1

There's no major significance, it's just street art.  

Answer 2

Indeed, there's some interesting street art to be seen. Here's my response to a previous question about those reflective sticker "robots" placed at various crosswalks around the District.

Answer 3

earthling, please decode this answer to find out:

296 we 392072 snif aqwoe soo xill alsew

and then + 224 =

the square root of 324463968496235829305217284.324697803246

including the title of emily dickinson's 12 poem

minus the 5th word that is in the number one bestselling book on the new york times fiction bestseller list

and you may find your answer (i said may, not will)

gweeb gwool (that is good luck in our language)