Try this challenge. Write a 30 word short story (any genre), but there's a catch. The first and third sentence must contain 5 words each while the second and fourth sentence must contain 10 words each.
Just as it says in the challenge prompt.
Someone knocked on my door.
When I answered, I didn't see anyone, which was strange.
So, I shut the door.
And when he knocked again, I shot him within range.