HEY - Rotational ambigram

Somebody asked me whether I could do a continuous ambigram, in a moderately cursive style.
I obliged, but I admit I was lazy. I am still less than proficient at vectorising thin shapes (I content myself using the 'ready-made' shapes available), so this may not yet be in it's best possible form.

I'd really appreciate comments on the readability, and perhaps even tips on vectorising ;)