I had asked this question since the early morning, and continued while I was in front of my notebook. I went hiking, and did some garden jobs in between, the question followed.
What is the colour of a shadow? A trivial question? Is black the answer?
Internet told me when we stand in the sunlight, some of the light is stopped while other rays pass on in a straight-line path. A shadow is formed where light ray cannot reach. Then a shadow should be in black, this is the law of Nature.
But trees told me differently when I was at Cerok Tokun. That is only an assumption of human which cannot be applied in the kingdom of trees. They insisted.
Yes, I shall honestly not to argue. All advices from my friends are valuable.
As I followed, I noticed their "shadows" appeared to be reflecting the original colours and were very lively. Then there is no reson shadows must be in black?
The "shadows" were seen twisting and dancing with the ripples, and I was reminded to record down this moment while being too focus on this beauty, and that of the blue sky with white fluffy cloud.

I was led to the shady area again. Everyone of these trees was simply too overwhelmed with my trivial issue. They showed me more evidence.
And finally I have to agree that shadows are not limited to only black. They are colourful.