In this task, you're given a pair of sentences, sentence 1 and sentence 2, that agree with each other. Your job is to alter sentence 2 so that the pair contradict each other. Generated sentences must be short, with less than 15 words. New information can be introduced. Avoid using pronouns to confuse the subject of the sentence.

Sentence 1: A man is standing on a ladder repainting a wall with the color blue. Sentence 2: There is a man painting
There is a man watching others paint

Sentence 1: A string quartet practices for an up-coming performance. Sentence 2: A string quartet practicing.
The woodwind section warming up for a performance.

Sentence 1: An adult male and a young boy are mixing together a yellow mixture in a large pyrex mixing bowl. Sentence 2: An adult male and a young boy are mixing together a substance in a pyrex mixing bowl.

An adult male and a young girl are mixing together a yellow mixture in a small pyrex mixing bowl.