People are pleasantly satisfied after a person on Twitter demonstrated how much ink is in a ballpoint pen, via smiley faces.
【結論】1本のボールペンのインクの量は29249スマイルである。 #夏休み#自由研究
Asuka Sato, a Japanese ballpoint pen artist, drew 29,249 smiley faces to see how much ink a Hi-Tec-C ballpoint holds.

On her first day of drawing, she discovered that one postcard (10 centimeters by 15 centimeters) could hold 600 smiley faces.

On day two she spent 10 hours filling postcards with smilies.
1本のボールペンに含まれるインクの量が気になったので軽い気持ちで調べてますが終わる気配がありません(現在8775スマイル) #夏休み#自由研究
It took Sato six days to empty the pen, covering 49 postcards.
1本のボールペンのインクの量について調べてます。だんだん終わりに近づいてきました(現在15846スマイル) #夏休み#自由研究
Which looks like this.

People were incredibly impressed with Sato's effort.
@satowasuka すご!スマイル綺麗✨✨✨ お疲れ様でした✨✨✨✨✨✨
"Awesome, beautiful smiles. Thank you for your hard work."
Sato, now a professional ballpoint pen artist, told BuzzFeed News she got a taste for drawing while doodling in college.
@satowasuka 正気の沙汰でない
"This is not sane."
"After working an office job for a year and a half, I became a ballpoint pen artist," she said. "I publish books and make merchandise in collaboration with companies."
すごい https://t.co/mlPpmqNt5d
"Wow."
Sato said that she got the idea for the project trying to find ways to avoid going outside.
"I'm an indoor person, so I started this project as something to do at home during the summer," she said.
To add a mind-blowing element to the piece, Sato told BuzzFeed News that she drew some faces without smiles. See if you can find them. 😉
@satowasuka FF外から失礼します こいつ笑ってないです 失礼しました
This post was translated from Japanese.