You are only missing one character:
I wrote it like that with the left side as stairs to represent the hard climb to enlightenment. I should mention a bit about my calligraphic style: At first, I spent a few years with my first two teachers learning the traditional scripts (I especially like the grass scripts). However, my current master has a different philosophy. He suggests that following traditional form is more like handwriting and that even the masters of long ago who wrote in those forms were masters because, like in tai chi or gong fu, they knew the form but bent it and transformed it beyond itself, transcending the form in other words. He often compares calligraphy to drawing portraits, saying that if you draw someone's picture in photographic realism they might as well have taken a photograph. Instead, we spend as much time learning the etymology of characters, and the many ways they have been written through time, to find the 'essence' of the word--in the same way as one drawing a portrait would look for the 'spirit' of the model. Then we learn about breathing properly and focusing Qi into the brush to capture that spirit. Funny enough, my master says that we foreigners can, in his opinion, learn to make better calligraphy because the characters are still pictures (art) to us whereas his Chinese students have to overcome their education, which has turned the symbols into mere words--the same words they think in.
The "Shadowy Portal" is the Daoist term for enlightenment. A famous saying is: "Entering the Shadowy Portal, they pass beyond the World of Dust to the realm of the immortals."
There are thousands of Daoist texts and commentaries (5400ish to be exact). If you are looking for English literature, on the other hand, Thomas Clearly has several good, though very dry, translations. Blofeld has a good overview called "Taoism, the Road to Immortality" (He also wrote the first English book on tea by the way). Alan Watts' final book "The Watercourse Way", finished after his death by a friend, is also great. From there, follow your heart and the network these books open up.
Here is a piece by my master, Wu Chung Chi (Wu Jiru). If you have access to issue one of AoT you can read more about him. Notice the tremendous difference in quality between master and student, his work and mine: