ART 2: We decided to switch places to teach her husband a lesson 

On the outside, we were almost identical. Same hair, height, voice, even the way we looked. Unless you knew us well, it was impossible to tell us apart. That's why the plan worked.
I arrived at her house as if I were my sister. I acted calm and quiet, just like she always did. But inside, everything was different. I wasn't afraid anymore. My sister's husband sensed it almost immediately.
At first, he simply stared longer than usual, as if trying to figure out what was wrong. Then he started picking at details. She'd placed the mug wrong. She'd answered wrong. She'd used the wrong tone.