Question about a hiragana/katakana worksheet

Found this at the Trancefuel website (it's a PDF).

There are several blocks which are subdivided into halves or quarters. Does anyone know what the purpose of this is? Maybe all the blocks were originally like that and this is a fainter copy?

Any clues?

Looks like a cool worksheet though... Apparently you fill in the blanks with the katakana corresponding to the hiragana next to them.

Wheeeee!

Nice file!
I've got some notepapers for practicing kanji that are all subdivided like that (into quarters, with those dotty outlines) for reference when writing so it's easier not to make the kanji look crappy.

I don't think they were all meant to be like that though... it seems like it's the same signs over and over that have them (like small tsu has the four pieces many times and "i" has the two pieces)...
There's probably some point to why only the ones that have it do have it.

It's for writing the words in katakana. It's divided into "foreign names," "foreign words," "animal sounds," etc. The ones with the single dotted line are there for guidance for writing the vowel lengthening mark in katakana. The ones that are divided into quarters are there to keep the small kana in proportion to the larger kana, i.e. the small ya in gachan and the small tsu in youroppa.

Ahh! It makes sense now that I've been doing them for a while. Just when I first looked at it, I was like, what the heck is this?