I'll start with the set up. a b c d e f g h ... <-V a' b' c' d' e' f' g' h' ...' a, b, c, d, and e are all .5 a light second apart. The primed letters are all moving with a velocity of .5c to the left. a, c, and e emit light when a primed letter passes. We know that all the primed letters are .5 a light second apart because b and d receive pulses from a, c and c, e simultaneously every second. Now what confuses me is that the nonprimed frame will see a primed letter pass every second and they will see the primed clocks ticking slower, but if we switch reference frames the primed will see the unprimed traveling at .5c see an unprimed pass every second and will also see the unprimed clock tick slower. This is relativity and I think I can swallow this because simultaneity is lost between reference frames. But as I was thinking about this I noticed that if at the instant captured above both frames set their clocks to t=t'=0 then every time a letter pass their clocks should agree. I.e. as b' passes a the nonprimed clock will read t=1 (it will also read some dilated time for the primed frame), but as a passes b' t'=1 in the primed frame (with the same dilation for the nonprimed frame as seen before). This can still make since with the loss of simultaneity. But I thought further... When would the primed frame see the light pulses from a, c, and e? It is clear from the nonprimed frame b will see c s first pulse (t=0) .5 seconds later and that b' would see this pulse some time later. From the primed frame though a, c, and e are pulsing as they pass therefore b' should see c s first pulse (t=0) .5 seconds later as well. The part that perplexes me is that every time a letter passes another letter their clocks should be synchronous, even though their times pass at separate rates. I.e. when b' passed a, the nonprimed frame read t=1 and when a passed b' the primed read t'=1. Both reading the same lapsed time for a particular event, at a particular place, but both experiencing this event not simultaneously. Thanks, I konw there must be a flaw some where I just havn't been able to find it yet.