Today I think I confirmed my earlier suspicions that we are trading against a computer - not a person. Late in the day I entered an order to sell 200 RMCF at 14.80. Level 2 showed best bid ARCAEX 300 @ 14.68 - ask ARCAEX 300 @ 14.83. Immediately, I mean immediately, after my 14.80 offer showed (literally 1 second after I hit the enyter key) a split second later the ARCAEX offer of 300 went to 14.79. To test my theory, and since I was starting a scale out, I waited about two minutes and cancelled my offer. No trade took place in this two min period. You guessed it. He went back up to 14.83 offer. I do not remember if his raise to .83 was immediate. The stock traded a few shares a few min later at 14.83/ .85 / .85 then 14.90 and was still offered at .90. I reentered my sell at 14.89 (thought I was screwing with a person, not a computer) and sure enough the ARCAEX offer went to 14.88, JUST AFTER IT PRINTED 1900 AT 14.91. (the 19.91 print occurred as I was entering my .89 offer.) 20 seconds later somebody took the .88 / .89 (me) and .90 &.91 offers. See atttached T & S from the 14.85 prints through EOD. No person could have under offered me that fast ( literally a split second on both entries). SO...... How do they do it?