Tested in build 3.4-SNAPSHOT-705 (spigot)
structure blocks don't show up like they should:

In-game:

Great job on all the textures so far, just the finishing touches!

Fixed in 731

sadly doesn't seem like it is fixed in 731. still shows as black blocks:

Seems good here....

oh no ... he has made a mistake, sorry - the blocks he has displayed at the top are 'jigsaw' blocks.

structure blocks are looking good (as are cauldrons and sunflowers - ooh yea)