multicol | -moz-column-span: all | -moz-column-fill: auto

# you should not see the word fail

block1
  block1 block1
  block1 block1
  block1 block1 block1
  damer block1 block1

block2
  block2 block2
  block2 block2
  block2 block2 block2
  damer block2 block2

block3
  block3 block3
  block3 block3
  block3 block3 block3
  damer block3 block3

block4
  block4 block4
  block4 block4
  block4 block4 block4
  damer block4 block4

fail
  fail fail
  fail fail
  fail fail fail
  fail fail fail