Canvas background

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 such as cut/copy/paste, and also keyboard entry.

The following keystrokes insert an operation

+ add
- subtract
* multiply
/ divide
^ pow
% percent operator
& integral
= Godley table
@ plot
# 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.