If one never saw the sea, they would be unable to imagine how vast it was. If one never saw the sky, they would be like a frog in a well, ignorantly thinking that it was only as big as the opening of the well.
Lu Sheng had originally thought the fire only had the few forms he knew, but after seeing the figure of the Eight-Headed Griffin, he realized that flames weren't just confined to those few basic forms.
For every single flame, its existence, heat, warmth, smoke, frequency of light... all of these were unique and part of its individuality. Every appearance had its connections. Once you understood one of them, you could subsequently figure out much of the rest.
By looking at the conditions and results, slowly, Lu Sheng achieved a deep understanding of the true nature and rules of some of the flames.
The golden flames burned out after a little while.