Taoist Master by training and zen master by profession, Liu HuaYang 柳華陽 (author of the famous Hui Ming Jing 慧命經） is the most controversial figure, due to his Taoist interpretation of Zen Dharma, essentially Liu maintained that they are the same. In his prose-poem (賦) "The moment of Zen" (禪機賦）， he documented his idea in poetic.
This is its entirety in Chinese:
He began with (my translation):
"Tao breeds heaven and earth, Dharma back to its Origin.
Its method uses both action and non-action,
follow the nature's signals for each right comment.
Its signals are subtle
watch out for the subtlety of appearance from nothingness
the bliss of tranquil Essence
showing its way through overcasting clouds.
When the sky is clean, and the moon can reflect Autumn's river,
Dharma of Hui Neng (慧能) cannot be known.
When Spring is misty like smoke
Cloudy sky has to be cleared so the one's heavenly eye can appear
Overcast rain has to stop before towering hills can be seen.
When lake is clear, a perfect moon will be reflected
when the background is dark, the form will be clear.
When compassion is cold, the heart of Zen will be steady
When mind is not sharp, the original essence will appear.
For lead （黄芽）and mercury (白雪), one must begin with the Essence of the Origin
For Buddha's sacred Lotus (地涌[金蓮]） and heavenly mandala （天花[亂缀]）, one must also begin with the true face of the Origin.
When one gathers, it is there
When it disperses, it is gone.
When one is out of it, one experiences this world (尘世)
When one is in, one experiences Nothingness."
And here comes Liu important phrase （有情下种,乃如来之妙用，无法枯禅,即道人之顽空。）
"With love one sows the seed, being a subtle wisdom of the Buddha; Without love one does dry zen meditation, being an Enlightenment seeker's stubborn Emptiness".
For Liu, Erotic love comes from the Essence of every sentient being (which ultimately comes from Tao). And the Buddha Dharma also makes use of this Essence. Instead of having this Essence "naturally" developed into erotic love, at the right moment a practitioner shall redirect it and use it to light up one's heart. The saying of subtle wisdom refers to Liu's concept of cleverly make use this energy from emptiness to jump start one's Dharma process.
Students of Freud psychoanalysis shall be able to see its similarity with id in one's personality (id, ego and superego). The sexual energy of id is censored by the superego (and hopefully being regulated by one's ego). In Liu's version of Buddhist Zen Dharma, sexual energy is allowed to "burst" out, bypassing the censorship of the superego (because one is in a meditative state). But instead of allowing it to satisfy the urge of id and ego, this energy is used to nurture the total personality, combining it into a totality, freeing itself from the conflict between its three parts (id, ego and superego). Of course, this is ONLY a possible Freudian interpretation as an extra reference for the interested readers. Nothing definitive is assumed.