EXP. 007
Wait For Me
You don't have to do anything. It grows slowly while it's open, and when you come back it makes up exactly the time you were gone.
How to play
Do nothing. Switch to another tab, come back, and it grows for the time you were away. It also tells you how long you were gone.
What it's made of
A page visibility event plus timestamps held in memory, and Canvas 2D drawing a line plant. No local storage is read or written.
Limits
While you watch, it grows a segment every 22 seconds, up to 7. While you're away it adds one every 15 seconds, up to 12 at a time and 18 in total. Close the page and it starts over. The PNG is saved locally.
What I was thinking while building it
The hard part was not adding buttons. It shouldn't wait for orders. You leave, you come back, and it quietly makes up that time. That sentence is the whole result.