For a helix with thickness, see spring (math).
f ə ɹ ɹ ə WORD_BOUNDARY h iː l ɪ k s WORD_BOUNDARY w ɪ ð WORD_BOUNDARY θ ɪ k n ə s WORD_BOUNDARY s iː WORD_BOUNDARY s p ɹ ɪ ŋ WORD_BOUNDARY m æ θ WORD_BOUNDARY