game_2048: 2048 game is confined within a 4*4 matrix. The numbers within the matrix start from 2. You can choose to move up, down, left, right to sum up two adjacent same numbers. After you make move, number 2 will appear in a place within the matrix where the value is 0. For some conditions like this: 2, 2, 2, 2, if you move left, the result will be 4, 4, 0, 0.

ascii_art_generator: Use ascii art to represent an image.

email: Include downloading email attachments, sending email(normal files and zipped files).
About sending zipped files: no idea why the attachment I received is a binary file which does not end with ".zip" no matter how I tried, but when I changed the name of file I downloaded to 'something.zip', it worked!! It's a zipped file now.

html_to_xlsx: Transfer file format from html to xlsx.