For those who want to study effectively.
"Red Sheet on Smartphone" is an app that allows you to use your smartphone as a red sheet.

If you use "Red Sheet on Smartphone" to view the text through the camera, the red text will disappear!
This is an app that makes learning easier.
It also has a library mode that allows you to apply a red sheet to saved photos. This allows you to create memorization books using saved photos and screenshots.

Please use it to memorize English words and study for exams and qualifications!