WRITING OBSTACLE
Your character sees everything in black and white. One day, they see but one colour in a world of monochrome. Describe their experience of this colour.
It could be a red balloon or a blue bird - this is a good way to really get into vivid and metaphorical descriptions!
Color Prompt 
They asked, "How could you possibly know what red is?"
I tell them "I don't. But I know a robin doesn't know how to be anything else."
A little scrap of fire against a nothing sky,
The dance on a mound of nothing soil,
For no other reason but being alive one second longer.
How can that bright spark of a song,
Somewhere between laughter and a whistle,
Given to the morning with that audacious charm
Be anything but red?