My first is a color, or the absence of light. My last follows 'snail', as it moves slower than a modern track. Together, I use knowledge to extort you, to my delight.

I am a clock that hates the dark, dependent on the sunlight’s mark.

I am a boundary with no wall, A door with no hinges, A keeper of light and secrets. When I part, another world appears.

I am a dark shape against the light, with no fine features shown in sight. Not the shadow cast at your feet, just your outline, dark and neat.

She stands where fear would reign, a girl with fire in her name. Like Joan, she hears the call, like Malala, she stands tall. Like Greta, she will not bend, for tomorrow, she will defend. Not queen by crown or throne, but brave in flesh and bone.