It's simple to fulfil the requirements, making it flow naturally is not. Also, any mistake early on in any paragraph will have cascading effects.

  Do you think its possible
  you can be both right and
  wrong? The feat might not
  be as crazy as the author
  claims to think. I myself
  can think of many ways to
  achieve it. Come to think
  of it, it may actually be
  even easier because lines
  in that guide afford more
  ways to be broken because
  they are longer. I am not
  even a native speaker.

I think the most "simultaneously observed forms" were brick-text with an acrosticon down the left-most column, or brick-text in iambic pentameter. I have attempted observing all tree, if ended badly.

  As somebody said, I am just a
  random guy on the Internet. I
  learned this language already
  as an adult never attending a
  single lesson. There is a lot
  of other people that know the
  language way better than me.

  Thinking that it must be hard
  just because it is for you is
  a well known bias.

Gigablah, I can't reply to your comment because apparently I am rate limited.

I am not saying it is easy. I am just saying it is not "most scarily/stunningly impressive linguistic feat".

I hope you can appreciate there is a lot of space between "easy" and "stunningly impressive".

  It is easy to do this. All you
  do is write some text upfront,
  and go line by line and swap a
  few words to make the line fit
  in the margin. Use small words
  to make it easier.

I can even think of an entire industry dedicated to countering this bias.