The canvas is not simply an inert place for the canvas items to exist. There is also a background context menu, giving access to the edit menu functionality, and also keyboard entry.
The following keystrokes insert an operation
+ | add |
- | subtract |
* | multiply |
/ | divide |
^ |
pow |
& | integral |
= | Godley table |
@ | plot |
% or # | start a text comment, finish with return |
Typing any other character, then return will insert an operation (if
the name matches), or otherwise a variable with that name.